The toucan’s bill is the largest relative to body size of all birds. The bill can modify blood flow and so regulates heat distribution in the body. The bill has a network of superficial blood vessels supporting its thin horny sheath made of keratin.
The toucan’s bill is the largest relative to body size of all birds. The bill can modify blood flow and so regulates heat distribution in the body. The bill has a network of superficial blood vessels supporting its thin horny sheath made of keratin.