The Threespine Stickleback, Gasterosteus aculeatus, inhabits northern coastal streams in North America along both the Atlantic and Pacific Oceans. Because the fish is so variable, some taxonomists have suggested that it comprises more than fifty species. Some years ago I wrote a poem about it. Here’s the limerick, along with my illustration:
The Threespine Stickleback
This stickleback’s armor is nifty;
Compared to the Ninespine it’s thrifty.
While three spines might seem
A taxonomist’s dream,
This species might really be fifty.