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Raptors kill hominids, kill cattle, kill giant moa

The views expressed are those of the author and are not necessarily those of Scientific American.


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No time for anything new: I figure this is pretty self-explanatory. For anyone who wants to follow up on some of the assertions boldly stated in the slide above, check out…

Berger, L. R. & Clarke, R. J. 1995. Eagle involvement in accumulation of the Taung child fauna. Journal of Human Evolution 29, 275-299.

- . & Clarke, R. J. 1996. The load of the Taung child. Nature 379, 778-779.

- . & McGraw, W. S. 2003. Further evidence for eagle predation of, and feeding damage on, the Taung child. South African Journal of Science 103, 496-498.

Matchett, M. R. & O’Gara, B. W. 1987. Methods of controlling golden eagle depredation on domestic sheep in southwestern Montana. Journal of Raptor Research 21, 85-94.

Nybakk, K., Kjelvik, O. & Kvam, T. 1999. Golden eagle predation on semidomestic reindeer. Wildlife Society Bulletin 27, 1038-1042.

Phillips, R. L., Cummings, J. L., Notah, G. & Mullis, C. 1996. Golden eagle predation on domestic calves. Wildlife Society Bulletin 24, 468-470.

Worthy, T. H. & Holdaway, R. N. 2002. The Lost World of the Moa. Indiana University Press, Bloomington & Indianapolis.

…. oh, and chapter 1 in Tetrapod Zoology: Book One. This is also a good time to mention my friend Steve Bodio’s brand new book An Eternity of Eagles: the Human History of the Most Fascinating Birds in the World.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com!

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The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. Boesse 7:19 am 11/10/2012

    To be quite honest, I was pretty surprised by just how dinky the skeleton of Haast’s eagle is when I first made it over to the Otago Museum across the street from campus. It doesn’t necessarily strike me (no pun intended) as something large enough to have been adapted for taking down large flightless ratites. Did it happen occasionally? Sure, there are those punctured Moa ‘hips’. But I’m skeptical that this was something Haast’s eagle was really adapted for. There are plenty of smaller, much easier, ‘less badass sounding’ prey items, such as Takahe and Pukekos, among other ground dwelling/flightless birds in prime Moa habitat.

    Link to this
  2. 2. BrianL 7:32 am 11/10/2012

    @Boesse:
    If you ask me, all bird skeletons look rather ‘dinky’. But why didn’t it strike you as adapted to taking very large prey? Are you judging from mere size or from the robustness of the skull, beak and talons?

    That being said, I’d think that takahe and pukeko might have been on the lower end of the prey size range for Haast’s Eagle, with small moa and adzebills being the average size of prey. My guess is that takahe, pukeko and anything smaller but larger than medium-sized passerines would have been the size range of the prey of New Zealand harriers, rather than of Haast’s Eagles.

    Having mentioned adzebills: Are they most likely to be highly abberant rails or to be eurypygiforms? I have to admit I far prefer the latter possibility.

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  3. 3. Heteromeles 10:20 am 11/10/2012

    Well, there’s the killing part, and then there’s the carrying away part. Lions can kill elephants under the right circumstances, but that doesn’t mean they drag them back to their cubs. Why couldn’t Haast’s eagle kill a moa, then dine on it in situ? It’s not like there were any hyenas (or even jackals) to chase it off the carcass, after all.

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  4. 4. Jerzy v. 3.0. 12:11 pm 11/10/2012

    E… technical. What is known about the eagle which killed autralopithecines? Is it Crowned Eagle or some paleospcies or what?

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  5. 5. Dartian 1:45 pm 11/10/2012

    Ratcliffe, P. R. & Rowe, J. J. 1979. A Golden eagle (Aquila chrysaetos) kills an infant Roe deer (Capreolus capreolus). Journal of Zoology 189, 532-535.

    That’s not really an example of an eagle taking large prey, however. An infant roe deer is small; at birth, roe deer only weigh about 1.5-2.0 kg (less than what an adult golden eagle does).

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  6. 6. amjustwondering 2:05 pm 11/10/2012

    What always bothers me about these cases is an illogical belief of the professional ornithologists. They have always insisted that the eagles upper limit to lift its prey is no more than their own weight, as if twice their own weight added up to some magic point. This is professional stupidity. The real issues would be something like wing-span and strength.

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  7. 7. dwbd 2:17 pm 11/10/2012

    Raptors killed one hominid and hominids kill thousands of Raptors every year with their giant monstrosity Industrial Wind Turbines planted willy-nilly throughout the pristine wilderness, a blight on nature if there ever was one:

    Deadly blades; death toll mounts as wind farms massacre birds of prey by Cathy Taibbi.

    Link to this
  8. 8. naishd 3:28 pm 11/10/2012

    Thanks for comments. Haast’s eagle: we have good evidence that it really was subduing and eating moa, plus there’s the fact that its legs and feet are extraordinarily large and robust – way more so than those of other big eagles. As for how regularly it killed giant prey, that’s difficult to answer, and Boesse may well be right that it was more frequently taking advantage of smaller prey. Haast’s eagle really does, however, have many tarsometatarsal and phalangeal features that set it apart from other eagles and look like macro-prey specialisations.

    What are adzebills? (comment 2). Well, that’s the big question, isn’t it? Galloanserine, metavian and core gruiform affinities have all been suggested recently. I don’t know, but I prefer the metavian hypothesis.

    More answers later…

    Darren

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  9. 9. naishd 3:48 pm 11/10/2012

    Other answers…

    Predatory behaviour of Haast’s eagle (comment 3): yes, Haast’s eagle has various cranial features which suggest that it was doing more reaching into carcasses than is normal for aquiline eagles, and this may well be because it was able to take advantage of those big moa carcasses for longer than would be possible in a continental environment with big mammalian competitors.

    What was the big African eagle that killed the Taung child? I always assumed from Berger and Clarke’s paper that it was a big, as-yet-unknown form, but the inference from more recent works it that a Crowned eagle was the guilty party. And that’s ok: Crowned eagles are known to have eaten juvenile Homo sapiens in modern times. In one case, skull fragments of an 8 year old child were discovered beneath a nest. As with the Taung child, this doesn’t mean that the eagle carried the whole body back to the nest, just some of it.

    Duly noted on inappropriate citation of juvenile roe deer paper. I have removed it.

    Darren

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  10. 10. N.T.F 4:26 pm 11/10/2012

    Ah, but of course you know Steve Bodio!

    Link to this
  11. 11. Gigantala 8:09 pm 11/10/2012

    “What are adzebills? (comment 2). Well, that’s the big question, isn’t it? Galloanserine, metavian and core gruiform affinities have all been suggested recently. I don’t know, but I prefer the metavian hypothesis.”

    If I’m not mistaken, genetic studies show that they were related to the Kagu+Sunbittern clade.

    At any rate, would we consider them to be New Zealands mini-phorusrhacid analogues? Their curved bills, as well as the absence of any other flightless carnivore bigger than the weka, seems to suggest that…

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  12. 12. Charles Hollahan 9:03 pm 11/10/2012

    I remember seeing an old European falconry book where a Martial Eagle was photographed attacking and killing a wolf. It was very impressive, not that I recommend it.

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  13. 13. Dartian 4:08 am 11/11/2012

    Darren:
    Haast’s eagle: we have good evidence that it really was subduing and eating moa

    Given that Haast’s eagle apparently preyed on moas, why don’t other large eagles regularly prey on other large ratites elsewhere? Obviously, ratite chicks are preyed upon, but what about adults? Why don’t (for example) African martial eagles prey on ostriches, or Australian wedge-tailed eagles prey on emus, by swooping down at them and piercing their heads with their talons? I don’t immediately see how extant ratites could effectively defend themselves against a serious aerial attack by a large raptor: they presumably can’t outrun it; they have short, ‘soft’ beaks that seemingly can’t be used for effective defence; and their principal means of defence, kicking with their strong hind legs, seems like an ineffective strategy against an attack from the air (unless, of course, ratites are far more agile than I’m aware of, and are able to jump high up in the air and kung fu-kick the crap out of the eagle).

    Of course, there’s the fact that even the largest eagle couldn’t fly away with a ratite carcass and would have to eat it on the spot – which means that it would eventually have to surrender its prey to the hyenas and other terrestrial scavengers which will inevitably show up on the scene. Still, one would expect the eagle to usually have time to eat enough of the ratite to make the effort worthwhile.

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  14. 14. BrianL 4:28 am 11/11/2012

    @Dartian:
    That’s quite an interesting mystery. Perhaps such actions have drawbacks that are not immediately evident or the chance of losing such prey to other predators is (or was) actually larger than it is or was. The risk of kleptoparasitism may have been even greater in your average Cenozoic ecosystem with a multitude of larger predator species around and in healthier numbers than today too.
    Continental ratites may or not be a numerous enough type of prey to specialise in though I can’t tell if you meant such predation as opportunistic or as specialisation.

    I do wonder if phorushacids hunted rheas. Presumably, they did.

    As for *Aptornis*, it seems reasonable to think of them as pseudo-phorusrhacids to me as in them being large, flightless and predatory birds.
    Of course, their specialisations seems to have been rather different in that they were very robust and did *something* very strainful with their beaks, skulls and hindlegs. What that could be apart from digging and burrowing, I don’t know. Their bill doesn’t seem all that built for crushing, to me. I could very well be wrong there, though. Phorushacids of course were more built for speed/kicking and had beaks suitable for slicing through flesh. Brontornithines may have been better analogues for adzebills than most phorusrhacids, though given that they were very robust and presumably quite a bit slower than your average phorusrhacid. Unfortunately, I believe the biology and ecology of brontornithines is poorly understood as well.

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  15. 15. naishd 6:50 am 11/11/2012

    Big eagles vs ratites: interesting stuff. Firstly, big eagles do attack ratites, even adult ones: Wedge-tailed eagles are documented emu predators (unsurprisingly, they are also documented killers of big kangaroos, and they have attacked people on occasion too).

    For other big raptors, the costs associated with ratite attack may outweigh the benefits. Other, smaller prey are typically available, and terrestrial mammalian predators may make ratite-killing unprofitable. Nevertheless I’d be fascinated to know if there are cases of adult ostriches being attacked or killed by big eagles – I’m not aware of any. Ostriches were widespread across continental Asia until geologically recent times (they may have persisted into historic times in some places, in fact), so there’s the possibility of Golden eagle – ostrich interaction.

    Note also that, while Golden eagles, Crowned eagles, Wedge-tailed eagles and so on can kill mega-prey on occasion, they are not morphologically specialised for this risky behaviour in the same way as Haast’s eagle was. However… have you ever looked at the feet of a South American Harpy? Its tarsometatarsus and phalanges are massively robust and its talons are huge – it looks ‘over-engineered’ for the prey it takes. Then again, maybe snatching monkeys, iguanas and sloths from branches requires ‘over-engineering’ of this sort. I do wonder, however, whether the Harpy used to kill bigger prey in the past than it does now. I don’t think there’s any work on Harpy functional morphology or foot strength. Indeed, note that there’s little work on raptor predation mechanics in general – Denver Fowler et al.’s PLoS ONE paper is the most important work out there. Huh, yet again, palaeontologists have to do the work that neontologists are supposed to have done (smiley).

    Darren

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  16. 16. naishd 6:58 am 11/11/2012

    Adzebills: I have to say, they don’t look much like phorusrhacid analogues to me – more like ‘super-rails’. That stout, downcurved bill is semi-cylindrical for part of its length and hence is not at all like the laterally compressed, hook-tipped phorusrhacid bill, and the body and legs are not those of a cursorial predator. Given their size (up to 20 kg), bill shape, and the habitats in which they’re found, I agree with Owen, Worthy & Holdaway and others that adzebills dug for big invertebrates, snapped up lizards and tuatara, and perhaps subdued seabirds and ducks during parts of the year. As I said, something like a ‘super-rail’ (or ‘super-weka’).

    Darren

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  17. 17. Dartian 7:10 am 11/11/2012

    Darren:
    Wedge-tailed eagles are documented emu predators

    Wow! I knew about wedgies killing large kangaroos, so I kind of expected them to be occasional emu predators too – but I didn’t know that any such cases were actually on record. You wouldn’t happen to have the reference(s)?

    I do wonder, however, whether the Harpy used to kill bigger prey in the past than it does now.

    How much is known about the ecomorphology and the feeding habits of the Papuan eagle Harpyopsis novaeguineae? What I’m getting at, obviously, is whether there’s any indication that it might sometimes prey on (adult) cassowaries. (Sounds outrageous, I know. But if other eagles may occasionally take astonishingly large prey, then why not Harpyopsis too?)

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  18. 18. naishd 7:17 am 11/11/2012

    I’ll dig out some Wedgie vs emu refs later – yes, it’s in the literature. New Guinea harpy eagles are not on record as cassowary predators. However, in modern times, they suffer extensively from singing dog kleptoparasitism – that is, the dogs are especially good at taking over kills that NG harpies make on the ground.

    Darren

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  19. 19. Gigantala 1:27 pm 11/11/2012

    Thanks for the replies. Indeed, maybe I shouldn’t be surprised; insular environments are terrible places for flightless raptorial dinosaurs. No wonder the dominant european predators were azhdarchids.

    As for eagles versus insular ratites, do notice that, based on the idea that the Haast and similar birds presumably fed on the ground on a single corpse for days at a time, it is very likely that predation was ridicuously uncommon when compared to mainland ecosystems. This, combined with the few numbers of large eagles and the utter absence of other macropredators, would make New Zealand a truly peaceful place.

    In Madagascar, it has been suggested that the extinct giant Aquila was a predator of Aepyornis and Mullerornis, though fossas and Voay would be quite kleptoparasitic.

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  20. 20. Tayo Bethel 4:20 pm 11/11/2012

    I thought singing dogs were excinct in New Guinea?

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  21. 21. eldri 5:08 pm 11/11/2012

    ***Singing dogs are the ‘village dogs’ of New Guinea. Like dingos in Australia, they are often found wild,where they
    are the largest land predator around.
    They may be cross-breeding with other dogs, in more settled regions, so that “purebred” individuals are scarcer, but I do not believe they are in any danger of extinction.

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  22. 22. vdinets 6:23 pm 11/11/2012

    eldri: are you sure? I always thought singing dogs were a purely wild population distinct from pariah dogs in villages.

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  23. 23. naishd 6:32 pm 11/11/2012

    The origins of the New Guinea singing dog (NGSD) are controversial, but (in recent times, at least) they do indeed seem to be a wild form. Janice Koler-Matznick says that there probably are still wild populations.

    Darren

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  24. 24. Christopher Taylor 12:43 am 11/12/2012

    If I’m not mistaken, genetic studies show that [adzebills] were related to the Kagu+Sunbittern clade.

    No, the molecular data available so far for adzebills have supported a relationship to rails. However, the recovered rDNA fragment was very short (I don’t have the exact size on hand, sorry). Morphological data have supported the kagu connection.

    Houde P, Cooper A, Leslie E, Shand AE, Montano GA (1997) Phylogeny and evolution of 12S rDNA in Gruiformes (Aves). In: Mindell DP (ed) Avian molecular evolution and systematics. San Diego, Academic Press, pp. 117-154.

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  25. 25. MA-writer 1:59 am 11/12/2012

    I’ve seen a red-tailed hawk eating a groundhog. It didn’t try to carry it off, just sat on it and ate it.

    Great horned owls kill skunks and cats. And they weigh, what, two kilos?

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  26. 26. Dartian 2:12 am 11/12/2012

    Gigantala:
    In Madagascar, it has been suggested that the extinct giant Aquila was a predator of Aepyornis and Mullerornis

    Who has suggested that?

    And was the larger* Malagasy Aquila really a ‘giant’? AFAIK, judging by the size of its preserved skeletal remains, it was about the same size as a golden eagle Aquila chrysaetos or a Verreaux’s eagle Aquila verreauxii; thus, it was large, yes, but not actually larger than the largest extant Aquila (Goodman & Rakotozafy, 1995).

    * Two fossil species of Aquila eagles are known from the Holocene of Madagascar: one large and one small species (Goodman & Rakotozafy, 1995).

    There was, however, another large extinct raptor in Madagascar in the Holocene: the Malagasy crowned eagle Stephanoaetus mahery. It was treated as specifically distinct from the African crowned eagle, S. coronatus, by Goodman (1994) – mainly on the basis of its slightly larger size. If ever there was a Malagasy raptor that preyed on the aepyornithids, it was probably this one rather than the Aquila species.

    References:
    Goodman, S.M. 1994. Description of a new species of subfossil eagle from Madagascar: Stephanoaetus (Aves: Falconiformes) from the deposits of Ampasambazimba. Proceedings of the Biological Society of Washington 107, 421-428.

    Goodman, S.M. & Rakotozafy, L.M.A. 1995. Evidence for the existence of two species of Aquila on Madagascar during the Quaternary. Geobios 28, 241-246.

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  27. 27. Gigantala 6:21 am 11/12/2012

    Most heresay, though not frankly not unreasonable. Mullerornis appearently was found near the remains of the larger Aquila species.

    The Mahery was most likely a lemur specialist. This could imply a niche partitioning, with the Aquila eagles hunting terrestrial prey while the Mahery hunted arboreal primates.

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  28. 28. JoseD 9:47 pm 11/12/2012

    @Naishd

    “Predatory behaviour of Haast’s eagle (comment 3): yes, Haast’s eagle has various cranial features which suggest that it was doing more reaching into carcasses than is normal for aquiline eagles, and this may well be because it was able to take advantage of those big moa carcasses for longer than would be possible in a continental environment with big mammalian competitors.”

    The above quote reminds me of a question: Is it safe to say that predatory birds avoid direct competition w/predatory mammals by flying to a perch to eat their prey? I was arguing w/someone about this a while back & wanted to make sure.

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  29. 29. David Marjanović 12:32 am 11/13/2012

    I do wonder if phorushacids hunted rheas. Presumably, they did.

    This has been suggested as the explanation for why rheas are such good endurance runners while nowadays nobody runs after them.

    heresay

    Hearsay. Hear + say.

    The Mahery

    IIRC it means “strong”.

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  30. 30. MA-writer 12:05 pm 11/13/2012

    New Guinea singing dogs are listed as vulnerable. Apparently they date back 30,000 years as a separate group. Is there a concensus on their status as a species or variety?

    One reason that eagles might not prey on ostriches (which are much bigger than emus) might be that other ostriches would drive them off or even kick them to death when they got down on the ground with their victim.

    Re a comment earlier on: I doubt it’s possible to identify the species of raptor from one or two claw holes in the skull of the Taung child.

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  31. 31. vdinets 8:29 pm 11/13/2012

    MA-writer: Singing dog is not listed as full species or even subspecies in recent literature. This is a bit inconsistent, since some much more recently introduced populations (i. e. the island fox of California) are routinely listed as full species. Personally, I think that both the singing dog and the Australian dingo should be considered valid subspecies (C. familiaris hallstromi & C. f. dingo), just as the island fox should be considered a subspecies group of the gray fox.

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  32. 32. vdinets 8:45 pm 11/13/2012

    sorry, didn’t close the italics tag :-(

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  33. 33. Heteromeles 12:07 am 11/14/2012

    Poor vdinets: Since they haven’t found the mainland population that the Chumash ancestors hypothetically dwarfed to create the island fox, I think it’s safer to say that they’re a proper island species (from the northern Channel Islands, assuming they evolved on glacial Santarosae) and were subsequently spread to the southern Channel Islands by the natives.

    While people have been keeping island foxes from archeological times (from grave remains) up until, erm, way too recently (by rumor on Catalina), they’re not tame animals by any stretch of the imagination. I know people in the fox program on Catalina, and I’ve heard enough of their stories to be quite sure of that.

    As for why the Indians moved the foxes around the islands: one hypothesis comes from the apparent fact that field mice used to be quite common on Catalina, at least according to the archeological record. It may have been exquisitely uncomfortable to camp out there when the first Indians got there, since the only terrestrial predators were golden-eyed rattlesnakes, and I suspect that setting up a village and storing food wasn’t much fun either. If I had to guess, I’d say the Indians brought the island foxes south just to get the mice under control. If so, they succeeded.

    Finally, about the legal status of island foxes: they are cute as the dickens, they’re tremendous fund raisers (their fans include the *extremely* wealthy people who own and run Santa Catalina Island), and they’re symbols for the entire island chain. While your argument has some merit in cladistic terms, in political and conservation terms, no one’s interested in demoting them to subspecies of the mainland gray fox.

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  34. 34. vdinets 1:57 am 11/14/2012

    Heteromeles: many dog breeds are very cute, in danger of extinction, and in some cases (like Carolina dog) remarkably non-tame. Why don’t we describe them all as full species? Just imagine all the funding we could obtain, and all the media attention! That’s what good science is all about, isn’t it?

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  35. 35. Jerzy v. 3.0. 4:59 am 11/14/2012

    Are there any recorded attacks of eagles on great apes, and how apes react to the sight of eagles?

    @singing dogs
    In few weeks in Papua New Guinea, I saw several times mongrels looking like “singing dogs” in the forest away from villages. I don’t think they are rare. As for conservation value, I guess it is very negative for any mammals, ground-living birds and reptiles. Actually, any mammals, even rodents, are very thin on the ground in PNG.

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  36. 36. Dartian 5:10 am 11/14/2012

    MA-writer:
    other ostriches would drive them off

    Do ostriches ever actually engage in such active defence of adult conspecifics against predators (of any kind)?

    I doubt it’s possible to identify the species of raptor from one or two claw holes in the skull of the Taung child.

    Well, there are still those who doubt that a raptor of any kind was involved at all. de Ruiter et al. (2010) suggested that the presumed talon marks and perforations on the Taung skull were actually caused by Raymond Dart’s (supposedly crude) preparation techniques in the 1920ies. de Ruiter et al. suggest – and here they are right, IMO – that we should withhold final judgement on the issue of eagle predation of the Taung ‘child’ until a proper scanning electron microscopy study of this specimen has been made.

    Jerzy:
    Are there any recorded attacks of eagles on great apes

    No. Which is the main reason why my gut feeling has always been rather uncomfortable with this eagle-predation-on-australopithecines hypothesis (I say this despite the fact that, like the late Carl Sagan, I too know that one should think with one’s brain, not with one’s gut – and despite the fact that I do like australopithecines, a.k.a. dartians!). I do not doubt that a large eagle – e.g., an African crowned eagle – could kill a juvenile australopithecine, but I strongly doubt that it would ever get a chance to do that except on the rarest of circumstances. Juvenile extant chimpanzees are virtually never predated upon by raptors, even though chimpanzees are almost everywhere sympatric with crowned eagles (and sometimes martial eagles too). AFAIK, no such cases have ever been recorded during the course of several intensive, sometimes decades-lasting field studies of chimpanzees. For example, Mitani et al. (2001) noted that during 5 years of field observations they never observed any attempts by crowned hawk eagles to attack chimpanzees, nor did they find chimpanzee remains in crowned eagle nests (in contrast, the eagles preyed extensively on virtually all the resident monkey species). Adult chimpanzees are apparently able to protect their juveniles quite effectively.

    If, as the data suggest, extant chimpanzees living in optimal crowned eagle habitat are virtually immune to eagle predation, I personally find it hard to believe that the similar-sized australopithecines would have been significantly more vulnerable to it. Sure, it may have happened occasionally (as suggested by anecdotal reports of crowned eagle attacks on modern human children) but presumably not to the extent that it would have been anything but exceptional, and surely not to such an extent that it would have been a significant selective factor in early hominin evolution.

    Oh, and sorry for yet another excercise in party-pooping, Darren. I know that you like your eagles and especially your mega-predatory eagles…

    References:
    Mitani, J.C., Sanders, W.J., Lwanga, J.S. & Windflder, T.L. 2001. Predatory behavior of crowned hawk-eagles (Stephanoaetus coronatus) in Kibale National Park, Uganda. Behavioral Ecology and Sociobiology 49, 187-195.

    de Ruiter, D.J., Copeland, S.R., Lee-Thorp, J. & Sponheimer, M. 2010: Investigating the role of eagles as accumulating agents in the dolomitic cave infills of South Africa. Journal of Taphonomy 8, 129-154.

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  37. 37. naishd 5:33 am 11/14/2012

    Heh heh, “attempt at party-pooping” indeed. I was unaware of the de Ruiter et al. (2010) paper until now and must check it out. However… the case for eagle predation as goes the Taung child is not limited to (possibly misinterpreted) score, puncture and nick marks (note that other workers have regarded the damage on the Taung child as consistent with eagle damage: Sanders et al. 2003), but also to the prevalence of mid-sized mammal remains in the same assemblage as the Taung child (remains that seem to be leftovers from a nearby raptor nest), plus there’s the discovery of eggshell in the same assemblage. However, I certainly agree that scepticism and more testing is warranted.

    As for chimps not being predated upon by Crowned eagles, just because it isn’t in the literature doesn’t mean it doesn’t happen (I know that at least some chimp specialists think it’s only a matter of time before this behaviour is documented properly), and we know for a fact that Crowned eagles have both attacked, and consumed the remains of, juvenile Homo sapiens.

    Ref – -

    Sanders, W. J., Trapani, J. & Mitani, J. C. 2003. Taphonomic aspects of Crowned hawk-eagle predation on monkeys. Journal of Human Evolution 44, 87-105.

    Darren

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  38. 38. Dartian 6:09 am 11/14/2012

    Darren:
    the prevalence of mid-sized mammal remains in the same assemblage as the Taung child

    Actually, it’s far from clear that the other Taung fossils are from the same assemblage as the australopithecine. As de Ruiter et al. point out in that paper, the fossil material collecting procedures in the 1920ies left much to be desired (also, much of the supposedly associated fossil material has subsequently been lost to science). Thus, the evidence for or against eagle predation of the Taung australopithecine really rests on the specimen itself only. I do concede, however, that the comparisons of the Taung hominid with extant primate cranial remains recovered from crowned eagle nests seem quite compelling.

    just because it isn’t in the literature doesn’t mean it doesn’t happen

    True, of course. But the chimpanzee literature is by now huge; if eagle predation is anything more than a super-freakishly rare occurrence, one would think that it really should have been recorded by now.

    at least some chimp specialists think it’s only a matter of time before this behaviour is documented properly

    Oh? I wanna names!

    we know for a fact that Crowned eagles have both attacked, and consumed the remains of, juvenile Homo sapiens”

    Have those cases actually been properly published? I have only ever come across secondary sources.

    Link to this
  39. 39. Gigantala 6:25 am 11/14/2012

    I would like to point out that what applies to chimpanzees might not apply to australopithecines.

    For one thing, chimpanzees are more robust, so they are more capable of defending themselves than weapon-less hominids.

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  40. 40. Dartian 6:39 am 11/14/2012

    Gigantala:
    chimpanzees are more robust, so they are more capable of defending themselves than weapon-less hominids

    Chimpanzees are (probably) stronger and fiercer than Australopithecus africanus was. But an adult Australopithecus africanus was certainly bigger and stronger than an eagle (of any species), and more than capable of killing one that threatened its young. (For the record, an adult Australopithecus africanus was also almost certainly much stronger than an adult modern human, even though it was much smaller.)

    Bottom line: unless they’re very small or young, primates are dangerous prey for an eagle. There is a recorded case of an African crowned eagle that tried to attack a juvenile Sanje mangabey Cercocebus sanjei but was intercepted and killed by an adult individual (Jones et al., 2006).

    Reference:
    Jones, T., Laurent, S., Mselewa, F. & Mtui, A. 2006. Sanje mangabey Cercocebus sanjei kills an African crowned eagle Stephanoaetus coronatus. Folia Primatologica 77, 359-363.

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  41. 41. naishd 7:45 am 11/14/2012

    Interesting stuff. I will follow up with references later, but I don’t wholly agree (that “primates are dangerous prey for an eagle”). Sure, any predation attempt can go badly wrong for the predator on occasion (there are cases where pumas have been killed by deer, wolves have been killed by bison, etc.), but big, powerful eagles have been recorded killing monkeys on enough occasions for us to think that this is something they do fairly regularly, and something that they’re pretty good at. When it comes to hominins, I’ll say again that big extant eagles are documented attackers of Homo sapiens, and that species like the Crowned eagle have probably killed human children. It’s circumstantial for sure, but, given this, it’s certainly easy to believe that a big prehistoric eagle could have killed a juvenile hominin that probably only weighed 12 kg or so.

    Darren

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  42. 42. Jerzy v. 3.0. 8:35 am 11/14/2012

    It would be interesting to track the primary source of this (apparently only one) report of child remains in martial eagle nest. Could a child be already dead of disease, exposure or eg. hyena attack?

    Especially “parts of the skull” sounds like the victim was killed by a hyena or similar. I don’t think an eagle could break child skull.

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  43. 43. JoseD 10:21 am 11/14/2012

    Just making sure my question in Comment 28 isn’t forgotten about.

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  44. 44. Dartian 10:30 am 11/14/2012

    Darren:
    I don’t wholly agree (that “primates are dangerous prey for an eagle”)

    Well, to that I’ll just say that one underestimates primates at one’s own peril. Puny Homo sapiens perhaps excluded, for their size they are surprisingly formidable animals: the mangabey in the above-mentioned report almost bit the neck off the eagle – an unusually large, healthy female – even though the latter had managed to grab the monkey by the chest with its talons. And they are resilient too: while still locked in combat, the mangabey and the eagle fell 25 m down from the tree to the forest floor. The monkey got immediately up, apparently none the worse for wear (the fatally wounded eagle was by then unable to move), and was seen a couple of days later alive and seemingly well.

    this is something they do fairly regularly, and something that they’re pretty good at

    Yes, but the eagles prey on monkeys by employing hit-and-run tactics. They make a surprise attack against one (small/young) individual at the troop’s periphery and then quickly fly away with it. They do not remain at the scene because the other troop members will certainly retaliate, and that would more often than not end badly for the eagle.

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  45. 45. Gigantala 12:05 pm 11/14/2012

    Still, there’s no reason to think a lonely juvenile wouldn’t be targetted.

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  46. 46. amjustwondering 1:30 pm 11/14/2012

    Does anyone know why professional ornithologists or anyone would insist that the upper limit an eagle could lift would be its own eight? I mean, other than some rough rule of thumb… What is magic about twice its own weight?

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  47. 47. Heteromeles 7:08 pm 11/14/2012

    @vdinets: Actually, I’ve seen exactly those arguments for preserving such “breeds” as the San Clemente Island goat, as well as ones that are more distinct and valuable. Admittedly, this was from people trying to conserve rare domestic breeds, but people still make the case. I should point out that, while I mock the San Clemente Island goat “breed” (and with good reason), most of the diversity in domestic plants and animals is as endangered as wild diversity. Industry doesn’t stop being stupid, just because it’s not wild.

    Thing is, there’s not a good case for making island foxes subspecies of the gray fox. There’s no good evidence that humans carried the northern island foxes out from the mainland (at least that I’m aware of–have they analyzed the DNA from those 6000 year old island fox bones yet?), nor are there dwarf mainland gray foxes. Nor were mainland gray foxes widely domesticated, anywhere in their range, or transported between tribes. Nor are island foxes widely domesticated, although they can be tamed, so long as you keep them in a cage. Even culturally, only the island Chumash had a fox dance.

    While it’s fun to ruffle feathers, there’s not a good case here for subsuming them into mainland gray foxes. They’re too distinct, both in anatomy and range.

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  48. 48. vdinets 8:20 pm 11/14/2012

    Heteromeles: Actually, there is (or was) another dwarf gray fox on Cozumel, and it, too, could be an ancient introduction. There is yet another small subspecies on Coiba. If evidence shows that the split between the mainland and the island foxes predates human arrival, it’s a different story, but so far, as far as I know, all data points at very recent colonization. The fact that the Chumash have a fox dance is interesting because they are the only extant tribe known to have moved to the islands and between them. But it doesn’t matter whether the introduction was human or natural: if it’s very recent and the only difference is size, I say it’s not a full species. US Endangered Species Act doesn’t differentiate between species and subspecies, so there is no reason to screw up taxonomy just for alleged conservation benefit.

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  49. 49. Heteromeles 3:41 pm 11/15/2012

    @vdinets: Actually, the southern islands were Gabrieleno, not Chumash, although they used Chumash technology. Catalina was reportedly the religious center for one Gabrieleno cult.

    As for other dwarf gray foxes, you’re right. I was thinking specifically about dwarf gray foxes on mainland California.

    The weird thing about the California gray fox is that, for most tribes (except for the Miwok and Island Chumash), it appears to have been a cultural non-entity. Outside the Miwok Silver Fox, and the Chumash fox dance, I don’t know of any references. Also, I have to point out that the Californian Indians as a group didn’t have domestic dogs. While the Chumash are interesting anomalies in many ways, I haven’t seen anything that says they kept dogs or any other domestic animal.

    While it’s not impossible for the Chumash or their ancestors to spontaneously domesticate a mainland fox that no one else has ever domesticated, create a dwarf race of said domesticate, and transport all of them out to the islands, leaving none of them behind on the mainland, I’d say that this seems very improbable. If they were that good at animal domestication, where are all their other domesticates? Why didn’t they have island-morph foxes in all their villages, and why aren’t they around today?

    However, and this is a big point, California Indians were pretty good at moving species around. The distributions of food plants (such as some Calochortus and certain oaks) really have to be taken with suspicion, because they tend to occur most heavily near known settlements. In California, the Indian’s landscape management skills approached agriculture in their complexity, but they weren’t farmers, with very few exceptions (ref: Kat Anderson, Tending The Wild)

    I have no trouble believing that some Chumash ancestor tamed some foxes, probably on Santa Cruz Island. I also have no trouble with the idea that they transported these tame foxes around the Channel Islands, partly as pets, and partly as mouse control. It’s unclear to me how long ago this happened (probably 8000 years ago, because that’s the length of the Catalina archeological record. It’s up to 14,000 years on the northern islands).

    Regardless of how they got there, the island foxes are now part of the island ecosystems. They are reproductively isolated and morphologically distinct, and it doesn’t bother me to call them separate species.

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  50. 50. vdinets 10:16 pm 11/15/2012

    I really don’t see the point of that argument. I never claimed that foxes were domesticated. It doesn’t even matter if the introduction was human or natural. What evidence is there of reproductive isolation? And what morphological difference is there, except for the size?

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  51. 51. Heteromeles 12:57 am 11/16/2012

    Reproductive isolation: the populations don’t interbreed. I don’t know whether they can interbreed if penned up and forced to, although given the size of the island foxes, I wouldn’t try with a female.Since I suspect such a breeding experiment is illegal under the Endangered Species Act, I doubt we’ll ever know. Therefore, they’re at least as reproductively isolated as a large majority of plants, and ditto with the morphology.

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  52. 52. vdinets 9:55 am 11/16/2012

    That’s called geographic isolation. Large rattlesnakes almost never survive crossing intestate freeways, so why don’t we call every population isolated by freeways a separate species? That would certainly be good for conservation!
    Considering that dog breeds easily interbreed when they are even more different in size, I don’t think there is any real reproductive isolation.

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  53. 53. David Marjanović 7:23 pm 11/17/2012

    True, of course. But the chimpanzee literature is by now huge; if eagle predation is anything more than a super-freakishly rare occurrence, one would think that it really should have been recorded by now.

    That said, it took forever till hunting with spears was documented. And what was the other recent surprise?

    Considering that dog breeds easily interbreed when they are even more different in size, I don’t think there is any real reproductive isolation.

    The question is which species concept you want to choose, and why.

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  54. 54. vdinets 7:23 am 11/18/2012

    David: certainly not PSC, since it’s not really a species concept – it is just a permission to lengthen your list of publications indefinitely by labeling all subspecies and isolated populations as full species. We’ve already had this discussion here more than once; let’s not start another round :-)

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  55. 55. Dartian 10:50 am 11/18/2012

    David:
    it took forever till hunting with spears was documented

    True, but such behaviour is in one very important sense different from having become the victim of predation.

    Chimpanzees can, for one reason or another, refrain from engaging in particular sets of behaviour – such as spear-use – when there are human beings observing them. But they can not hide having been predated upon; even if their deaths are not seen or their bodies are not recovered (which is something that the researchers will surely attempt to do, if at all practically possible, in order to perform a post-mortem examination), their disappearance from a closely monitored troop will not go unnoticed by the researchers. Even if they survive having been attacked by an eagle they should be marked afterwards by tell-tale wounds and scars (which are also difficult to hide). I’m unaware of any records of such suspicious disappearances* or of apparently eagle-wounded survivors. That’s negative evidence, admittedly, but, considering the intense level of detail that wild chimpanzee research has come down to (being able to follow almost the entire life histories, from birth to death, of specific individuals), I personally find the lack of that kind of observations quite telling.

    * “Suspicious disappearance” meaning: under circumstances specifically suggesting eagle predation.

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  56. 56. David Marjanović 11:28 am 11/18/2012

    certainly not [the] PSC

    It’s not like there are only two species concepts, you know. There are at least 147, and they all give different results when applied.

    True, but such behaviour is in one very important sense different from having become the victim of predation.

    Point taken.

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  57. 57. vdinets 2:27 pm 11/18/2012

    Dartian: wouldn’t it be more logical to expect eagles to refrain from attacking chimps when there are humans around than to expect habituated chimps to use some hunting methods and not others in human presence?

    David: true, but I am not aware of any other species concept that would allow splitting species based solely on geographic isolation.

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  58. 58. Dartian 2:37 am 11/19/2012

    wouldn’t it be more logical

    This sub-discussion isn’t about what’s “logical”. We are not discussing hypothetical or theoretical acts of eagle predation – or at least I am not discussing that; such thought exercises don’t really interest me all that much. What I’m interested in is actual evidence of eagle predation on chimpanzees. Such evidence either does exist or it does not. If anyone has such evidence to present, I’ll be all ears. Otherwise, meh!

    to expect eagles to refrain from attacking chimps when there are humans around

    By raptor standards, crowned eagles aren’t particularly shy of humans. Human presence doesn’t seem to deter these eagles from attacking monkeys; the eagles have certainly been observed (and even filmed) doing just that on many occasions (see, for example, comment #40 above). This in spite of the fact that no species of African monkey (with the possible exception of baboons) has been studied even nearly as extensively or intensively as chimpanzees have been.

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  59. 59. vdinets 7:10 am 11/19/2012

    Dartian: OK, you convinced me :-)

    BTW, many years ago I witnessed an attack on a group of howler monkeys by a harpy eagle. The bird had some difficulty pulling the monkey off the branch. Other howlers, however, ran away in obvious panic and didn’t show any sign of considering coming to the victim’s defense. Of course, howlers are big only by Platyrrhinine standards.

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  60. 60. Dartian 8:05 am 11/19/2012

    Other howlers, however, ran away in obvious panic and didn’t show any sign of considering coming to the victim’s defense.

    Were there adult males in the group? There is a report in the literature (Eason, 1989) of a male red howler monkey Alouatta seniculus charging and finally chasing away a harpy eagle that tried to attack the female howlers in its troop. (Admittedly, the harpy eagle was not fully adult. Still, the male howler didn’t seem to be particularly intimidated by its talons, with which the eagle tried to fend off the monkey’s aggressive swipes at it.)

    Reference:
    Eason, P. 1989. Harpy eagle attempts predation on adult howler monkey. The Condor 91, 469-470.

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  61. 61. vdinets 9:50 pm 11/19/2012

    Dartian: yes, I think there were (but it’s been 17 years ago).

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