Answers from Dr. Mikael Fortelius
Read Dr. Fortelius's answers to your questions.
Q: If all of the dinosaurs went extinct, from what did the new generation of prehistoric beast evolve? Some of these animals look similar to some of the dinosaurs.
Thank you,
Janet Cameron
A: Dear Janet,
Some of the large mammals may look a bit like dinosaurs but they are not descended from them. Mammals and dinosaurs are both very old groups, and mammals existed already at the time of the dinosaurs. When the dinosaurs went extinct some mammals survived, and these survivors gave rise to all later mammals. For some reason dinosaurs seem to have been better at being large, and mammals started to grow large only after the dinosaurs had died out.
It is interesting to think about why some large mammals look a bit like dinosaurs. The main reason for this is that large animals have to be built in certain ways in order to function well, so they tend to have similar builds and proportions. Similar lifestyles increase these similarities by a process called convergent evolution. A long neck is a very common attribute of very large, four-legged plant eaters, for example. (An elephant has a short neck, but its marvelous trunk does the same job, probably better.)
I hope this answers your question! — Mikael Fortelius
Q: Where did the largest land animals thrive?
— S.R.
A: Dear S. R.,
Generally speaking, the largest animals have thrived in the oceans (whales) and on big continents (dinosaurs). If you are thinking about mammals it seems that the largest species known to science have lived on the largest continents, Asia and North America. These are the indricotheres and the mammoths, the largest of which may have been as heavy as 15,000 kilograms (33,000 pounds). Other large mammals have rarely weighed more than 5,000 kilograms (11,000 pounds), and even 2,000 kilograms (4,400 pounds), like a white rhino today, is very large for a mammal.
Very large animals probably had very large home ranges, and were therefore probably not confined to particular kinds of environments. Whether they lived in herds or alone, they needed a lot of space in order to maintain a population large enough to survive.
I hope this answers your question! — Mikael Fortelius
