The largest animal to have ever lived is the Sibbald’s Rorquel (as you all no doubt know). This (see attached image) is the mature foetus of a Fin whale, the second longest whale. This image clearly shows the tooth buds on this baleen whale, which no longer forms enamel and the tooth remnants are reabsorbed and don’t break the skin. Like all mammals, whales have hair. They also have legs in formation like land mammals, some even weight bearing. Unlike land mammals, they give birth to their young, tail first. We now have some wonderful fossil examples showing whales with walking legs, blow holes gradually moving position and new feeding mechanisms of suction, as well as the above example, showing simultaneous baleen filters and rudimentary teeth.
Cetacea are very well represented on the Explorer tree. Who filled this out? Thanks! I recall doing some extant ones. If anyone wants to check it, I have a comprehensive list of extant ones if needed. How do you think they weigh really big whales?
In the UK, where I am based, we only have 100 native mammals, but to my knowledge, no single human being has ever seen them all, by way of wild or captive. Now there's a challenge! This is largely due to the obscure cetaceans. We are not big on reptiles or amphibians either, with just 13. Things are a lot better with birds and fish, and of course inverts. We don’t have much in the way of dangerous wildlife either. Just one venomous snake (which is not deadly). If hedgehogs are considered venomous, they are negligible. We have no native scorpions (just a few pockets of imported ones in the wild, but not dangerous). No dangerous spiders or centipedes. Bees and wasps are mild. We have no bears, big cats or wolves. Some cattle, deer and boar might butt you. Foxes, beavers, wildcats and otters (and crabs and lobsters) may nip you if you annoy them. There’s no cone snails. Some jellyfish can be dangerous though. But basically, if you are rambling or swimming in or around the UK, you are pretty safe. And we do have Blue whales!