This year, animals of all shapes and sizes surprised us with amazing abilities we didn’t know they had. From powerlifting to walking on the underside of water, these are the creature capabilities that most impressed us in 2021.
Sea slugs that grow new bodies
In a spectacular feat of whole-body regeneration, some Elysia sea slugs can grow a new body from just the head (SN: 4/10/21, p. 4). This feat may come in handy when animals are riddled with parasites and need a fresh start. The head simply detaches itself, crawls away and regrows an entirely new body, including the heart. These are the only animals with a heart that are known to regenerate so much of themselves.
Squirrels that parkour
We’ve all seen squirrels pull off death-defying maneuvers, but now we know more about how the rodents pull off their stunts. Like masters of parkour — the sport in which people leap, bounce and climb through an obstacle course — squirrels gauge the bendiness of branches when jumping. The rodents also use parkour-style jumps off of vertical surfaces to slow down and stick landings, researchers found (SN: 8/28/21, p. 14).
Animals that eat surprising animals
This year upended notions of predator and prey, revealing animals making meals of one another in surprising ways. Researchers found that more than 40 species from 11 families of spiders eat snakes, using sticky silk and venomous bites to subdue serpents up to 30 times their size (SN Online: 8/4/21).
What’s more, one Seychelles giant tortoise apparently didn’t get the memo that tortoises are gentle herbivores. It was spotted stalking, catching and eating a bird chick whole, the first documented example of a tortoise hunting prey (SN: 9/25/21, p. 5).
A beetle that walks on water, underwater
A water strider’s ability to walk on water is incredible enough, but the tiny water scavenger beetle flips the script: It walks on water upside down, clinging to the water’s surface from below (SN: 7/31/21, p. 13). The insect may use a small air bubble to pin its belly to the underside of the water’s surface, but just how it steps without breaking the water’s surface tension remains a mystery for now.
A bird that mimics a flock
The male superb lyrebird lives up to its name with its excellent vocal abilities, mimicking nearly any sound it hears in its Australian forest home — even chainsaws and cameras. Now scientists have recorded the bird mimicking the sounds of several other bird species at once — replicating an entire soundscape. It’s the only known animal with this talent (SN: 3/27/21, p. 12). Because the lyrebird mimics multiple alarm calls in particular, researchers aren’t sure if it’s also trying to sound an alarm or just showing off for mates.
Spiders that lift prey up to 50 times their own weight
In an innovative take on a pulley system, some spiders, including black widows, can hoist heavy prey up, up and into their webs using only strands of their silk (SN: 2/27/21, p. 13). Researchers observed the spiders attaching strand after strand from their main web to large prey such as lizards, with each strand just a bit shorter than the last so that the stretchy silk slowly reeled in the prize.
Polar bears that wield weapons
In a macabre example of tool use by animals, polar bears sometimes kill walrus by bashing them with large chunks of stone or ice (SN: 8/28/21, p. 16). Inuit hunters have long reported polar bears attacking prey this way, and a review of historical and modern documentation confirms that stone-wielding polar bears are a real phenomenon. This puts polar bears on the list of tool-using animals, including crows, chimpanzees, elephants and, of course, humans.