Toco Toucan

A Bill That Sheds Heat

The toco toucan carries the largest beak relative to body size of any bird, and it also works as a radiator. Adult toco toucans can widen the blood vessels in their beaks depending on the temperature, letting heat escape from the bill. At air temperatures above 28°C (82°F), the bill carries away an average of 60 percent of the bird’s non-evaporative heat loss.

A vascular radiator Relative to its size, the toucan’s bill is one of the largest thermal windows in the animal kingdom, rivaling an elephant’s ears in its ability to radiate body heat.

The Biggest Bill for Its Size

The toco is the largest and heaviest toucan, up to 61 centimeters (24 inches) long and 860 grams (1.9 pounds). The oldest toco toucan in the AnAge longevity database lived 16.2 years, in captivity. Its bill can make up 30 to 50 percent of its total body surface area, yet it accounts for just one-twentieth of its mass. Under the surface is a sandwich: a shell of overlapping keratin tiles, each about 50 microns across, around a core of bony foam. The bill is the toucan’s main foraging tool, letting it reach into tree holes and grasp fruit from surrounding branches.

Fruit Thrown to the Throat

Many birds move food to the throat with the tongue. A toco toucan does not. It places a piece of fruit at the very tip of its bill and leans its head back, projecting the food straight into its pharynx. Its tongue never touches the fruit. Tongue movement instead goes with a widening of the throat that lets the food reach the esophagus.

Life in Semi-Open Country

Toco toucans range from Guyana south to Argentina and from central Brazil west to southeastern Peru. The toco is the only non-forest toucan, found mostly in dry, semi-open country with scattered trees, such as woodland and savanna, and along forest edges. In Brazil it is abundant in the cerrado. It relies on seasonal fruit, so it moves from one habitat and region to the next to feed. It eats a great many figs and other fruit, and occasionally insects and other birds’ eggs, including those of hyacinth macaws. When foraging, toco toucans travel in small groups through the canopy, gliding in single file from site to site. Jaguars, snakes, coatis, and eagles are among their predators. The IUCN Red List classifies the species as Least Concern.