This is a lot of fun. Plug in two species or taxa and TimeTree will give you our best estimate of when they last shared a common ancestor. Drawing on a multitude of sources, you can look through the database and use TimeTree as a launching pad for further research.

Here are some sample results:

• Dogs and Cats, 57.5mya
• Dogs and whales, 82.8mya
• Whales and sharks, 523.1mya
• Dogs and oak trees, 1407.8mya

Fun suggestion – play the ‘higher or lower‘ game with pairs of taxa.