Is it true that kangaroo can only move their legs at the same time, like they can’t move them independently leg humans or dogs do?
yes with an exception: when kangaroos are on land, they use their legs together for hopping, but when they swim, they alternate which leg is kicking just like humans and dogs do!
so they CAN, they just don't unless they think they need to.
This has not always been the case however! Australia used to have another group of kangaroos called the sthenurines, also known as "short-faced kangaroos" (skeleton A below). They were proportioned quite differently, with larger bodies and shorter legs, feet and tails:
They were so differently proportioned, and some species grew so large, than hopping like a modern kangaroo was probably physically impossible for them, so researchers have proposed that they walked bipedally instead!
Members of Sthenurinae – an ancient family of kangaroos that lived until 30,000 years ago - likely preferred walking to hopping.
There are multiple delightfully cursed reconstructions of this behaviour which makes them look more like a person running around pretending to be a dinosaur than anything else
