Biology
Anti-Predator Adaptations in Stickleback Fish
Quick fact
Freshwater stickleback populations repeatedly evolve reduced armor compared to their marine ancestors, sometimes in fewer than 10,000 years, in response to different predator communities—making them a premier model for studying rapid evolution.
Why this is interesting
A small fish that lives in streams and seas may seem unremarkable—yet it is armed with razor-sharp spines and a suit of bony armor. Why would such a tiny creature evolve such formidable defenses, and what happens when those defenses come with hidden costs?