Certain physical characteristics of puffins and penguins make them appear more closely related than they are. Although puffins are shorter than penguins, barely breaking the 1-foot (0.3-meter) mark, they have matching white bellies and black overcoats. Both walk with a teeter-totter motion on orange webbed feet.
Socially, the seabirds have a lot in common, preferring to hang out and nest in large numbers. Although various terms may apply, groups of penguins are called colonies (rookeries refer to nesting penguins), and puffin clans are referred to as circuses and puffinries. Macaroni penguins may band together in breeding groups of up to 2.5 million birds [source: Reynolds]. Because they enjoy being around their own kind so much, puffins will readily approach wooden puffin replicas that ornithologists station at nesting sites in order to lure them in and observe their habits. In addition, both male and female puffins and penguins often mate for life.
But as much as we may adore each bird's awkward gait and smartly tailored feathers, let's get one thing straight: Penguins aren't puffins, nor are puffins penguins.