I think the coolest thing I’ve worked on are the monotreme mammals. These are really ancient relatives of us and split off the other mammals about 190 million years ago. They evolved into only two really crazy shapes as far as anyone can tell – one is the Echidna or spiny anteater, the other one is the duck-billed platypus. These two are really important for understanding mammalian evolution because they kept some ancestral traits – for example, they are the only mammals that still lay eggs. On the other hand, they came up with some strange things – e.g. the platypus developed an electro-sensitive beak with which to locate prey under water, and Echidnas have a poisonous spur with which they can defend themselves. I did some work on their development and found out that that was also really strange. They are nearly the only limbed vertebrates that develop their limb bones from the outside in; all other species (except, strangely, the European mole) do it the other way.
Sulawesi crested macaques. These are black monkeys that live in Indonesia, and in a zoo near Portsmouth. Unlike similar species of monkey, they get on very well with each other and are usually nice and friendly.