The –est Animals

Why crested penguins lay mismatched eggs

Extreme penguin egg favoritism could be quirk of migration

macaroni penguins

MISMATCHED OFFSPRING When macaroni penguins convene at a breeding site (shown), females lay some of the most size-mismatched eggs known among birds.

G. Crossin

By Susan Milius

- More than 2 years ago

In crested penguin families, moms heavily favor offspring No. 2 from the start, and a new analysis proposes why.