Titanis walleri, The American terrorbird by Tuomas Koivurinne
Smilodon and Thylacosmilus, an example of convergent evolution illustrated by Carl Buell.
“Under certain conditions, two lineages will evolve into very similar-looking forms. The top animal is a saber-toothed cat, related to lions and tigers. The bottom one is a marsupial, more closely related to kangaroos and opossums.”
Nimbadon by Peter Schouten
“The long-extinct Nimbadon was the largest arboreal marsupial herbivore ever to have lived and it was well suited to life in the treetops” Keep reading at UNSW
Hermit Crab Vacancy Chains
As shells are a limited resource, some hermit crabs have evolved a behavioural mechanism for exchanging old shells. When a new shell is found, the crabs queue up from largest to smallest. When the largest crab moves into its new shell, the second largest moves into the newly vacated shell, leaving its old shell for the third and so on.