Is it a bird?
Is it a bee?
Perhaps it's a little of both.
A hummingbird.
Of course, a hummingbird isn't an insect, but now biologists have discovered that insects such as bees can unlock some enduring hummingbird mysteries.
Hummingbirds are warm blooded, hollow boned and feather winged, just like all birds.
But they stand out with an impressive list of features and some extreme biology.
They're the smallest of birds.
One species measures just 5 cm from beak to tail.
But relative to its size, the hummingbird has the largest brain of any bird and it also has the largest heart of any animal relative to its own body weight.
