Some time in the late 1940s, a very patient, elderly beaver called Geronimo was put in a box, flown to an altitude of between 150 and 200 metres, and tossed out the side of an aeroplane. Over and over and over again. He didn’t know it at the time - because beavers - but each time Geronimo survived the trip back down to that little flying field in Idaho, he was bringing one of the nuttiest solutions to wildlife relocation ever dreamed up closer to reality.

It was 1948, so just after the end of World War II, and people were beginning to seek out new homes in the town of McCall and around Payette Lake in Idaho, “and in the process, kind of moved into where these beavers had been doing their things for decades - centuries - and beavers became a problem,” Steve Liebenthal from the Idaho Fish and Game Department told Samantha Wright at Boise State Public Radio.

The clash between the beavers, in their abundance, and the new locals resulted in a whole lot of damage to irrigation systems, orchards, and other kinds of farming efforts, so the Fish and Game Department staff were tasked with transplanting the beavers to a more suitable habitat. Which was cool, because past experience had shown that transplanted beavers were great at setting up new colonies, multiplying, and providing valuable environmental services such as storing water, reducing the risk of flash floods and erosion, and improving the habitats of other mammals, fish, waterfowl, and plants in the area. The only problem was the actual transplanting process.

In Idaho, the various mountains, heavily forested landscape, and lack of roads made beaver transplantation a difficult and convoluted process, as Elmo W. Heter from the Idaho Fish and Game Department described in a 1950 edition of The Journal of Wildlife Management. First, the targeted beavers would be packed into boxes, and spent days strapped to a horse or a mule, enduring the heat, dust, bumps, and general lack of breathing space on their way to the home of a designated conservation officer. By the time they'd arrive, it’d be almost dark, so they’d have to spend the night with a strange conservation officer they’d just met. What even would they have talked about over tea and biscuits?

In the morning, the beavers would be loaded into the conservation officer’s truck and transported to the end of the road, where they'd be forced onto another packhorse for the long journey to their final destination. Understandably, throughout the whole ordeal, the beavers got stroppy, the horses’ delicate senses were offended, and the conservation officers risked a good, old-fashioned mauling, as Heter explains below:

"Beavers cannot stand the direct heat of the Sun unless they are in water. During transportation, they must be constantly cooled and watered. Sometimes they refuse to eat. Older individuals often become dangerously belligerent. Rough trips on pack animals are very hard on them. Horses and mules become spooky and quarrelsome when loaded with a struggling, odorous pair of live beavers. These problems involve further handling and too frequently result in a loss of beavers.”

They needed a faster, cheaper and more humane way of getting these beavers from A to B, and the solution they came up with? Planes and surplus World War II parachutes. And here’s where our friend Geronimo makes his greatest contribution to science. Says Heter:

"Satisfactory experiments with dummy weights having been completed, one old male beaver, whom we fondly named ‘Geronimo,' was dropped again and again on the flying field. Each time he scrambled out of the box, someone was on hand to pick him up. Poor fellow! He finally became resigned, and as soon as we approached him, would crawl back into his box ready to go aloft again.”

A tough job, but a thankless one? Not even a little bit!

"You may be sure that ‘Geronimo’ had a priority reservation on the first ship into the hinterland, and that three young females went with him. Even there he stayed in the box for a long time after his harem was busy inspecting the new surroundings. However, his colony was later reported as very well established.”

“He was sent to his own little piece of paradise, with three lovely young beavers,” Liebenthal told Wright at Boise State Public Radio.

Thanks to Geronimo, 76 beavers were successfully transplanted during the fall of 1948. The boxes the Fish and Game Department officers used could carry two live beavers each, and they were heavy enough to deploy the parachute immediately, but light enough to end the trip with a gentle landing. Heter describes how the weight of the boxes kept them shut on their way down to Earth, but the beavers were able to easily crawl out once they'd landed in their new home - one of a selection of small, open meadows dotted with streams. These new habitats were part of what’s now considered to be the largest protected roadless forest in the lower 48 states, says Liebenthal.

There was one casualty - the linen lashings that kept its box together in mid-air broke, and the curious beaver managed to nose its way out and climb on top. "Even so, had he stayed where he was, all would have gone well; but for some inexplicable reason, when the box was within 75 feet of the ground, he jumped or fell from the box,” says Heter.

The following year, the team revisited their transplanted beavers and found that they’d all built dams and houses, bred, and stored food for themselves. The cost of transplanting them was way down from when they were strapped to horses and driven around by conservation officers - just $30 for four beavers, which Wright says equates to about $294 dollars today. If the parachutes were collected and returned, this cost would be halved.

Wright asked Liebenthal why the practice came to a halt after those 76 airborne beavers, and he told her that, most likely, the Idaho Fish and Game Department officers had done their job. Seventy-six was enough to restore the balance between humans and beavers around McCall and Payette Lake. And right now, somewhere in the Idaho wilderness, the children of brave Geronimo will have no idea what any of us are even talking about. Because beavers.

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