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The arteries and veins intertwine in the legs, so heat can be transferred from arteries back to veins before reaching the feet. Such a mechanism is called countercurrent exchange . Gulls can open a shunt between these vessels, turning back the bloodstream above the foot, and constrict the vessels in the foot.
In birds with webbed feet, retia mirabilia in the legs and feet transfer heat from the outgoing (hot) blood in the arteries to the incoming (cold) blood in the veins.The effect of this biological heat exchanger is that the internal temperature of the feet is much closer to the ambient temperature, thus reducing heat loss.
Birds are a group of warm-blooded ... 14 Tibio-tarsal articulation, 15 Tarsus, 16 Foot, 17 Tibia, 18 Belly ... it travels through venules then veins and back to the ...
Adding to this conundrum are fossilized footprints of bird-like tracks that are 210 million years old—a good 60 million years before the arrival of the genus Archaeopteryx, one of the oldest ...
A new analysis of three-toed fossil footprints that date back more than 210 million years reveals that they were created by bipedal reptiles with feet like a bird’s.
Bird anatomy, or the physiological structure of birds' bodies, shows many unique adaptations, mostly aiding flight.Birds have a light skeletal system and light but powerful musculature which, along with circulatory and respiratory systems capable of very high metabolic rates and oxygen supply, permit the bird to fly.
Pages in category "Bird anatomy" The following 66 pages are in this category, out of 66 total. ... Bird feet and legs; Bird vision; Bird wing; Brood patch; Budgerigar ...
Because birds are exposed to a wide variety of toxic gases and air borne particles in the environment, studies have used birds to measure air quality. [7] Not only is a bird’s respiration adapted to handle high-altitude flight, but so too is the circulatory system. In general, birds have larger heart sizes and higher cardiac output.