Conservation charity WWF said it had obtained footage more than 100 walrus carcasses spotted by US Geological Survey (USGS) researchers flying near Icy Cape, Alaska, after a massive herd of walruses congregated on the shore.
A preliminary report by experts in the US concluded 131 carcasses, mostly of calves and young walruses, found in the area had been trampled to death by other walruses.
WWF said the reduction in Arctic sea ice cover was forcing the animals to take refuge on land in large numbers, in "haul outs" which can lead to violent stampedes.
Geoff York, WWF's lead Arctic species biologist, said: "With the rapid melting of Arctic sea ice due to climate change, walruses are losing their habitats and are being forced to congregate on land in massive numbers, often in the thousands.
"This is a very dangerous situation as it can lead to stampedes and the trampling of walruses. As is evidenced by the Icy Cape situation, young walruses are particularly vulnerable."
Mr York said he had observed 20,000 walruses congregating on the shore of Russia's Cape Schmidt last month and warned the animals, who feed on seafood from the ocean floor, could run out of food when they are in large groups.
"As the sea ice retreats further out into the deep Arctic Ocean, walruses are unable to find food and are therefore coming ashore in huge numbers and in places they hadn't been before.
"Once on shore, the walruses are limited in how far out they can forage, especially females and the young.
"If 20,000 walruses are all trying to find something to eat in one area, it won't be long before the food runs out," he warned.