Hummingbirds Hummer Adaptations: The Body Strength and Determination in a Tiny Package Click for labeled photo Fully one-third of a hummingbird's body weight is in its chest muscles, which power its wings. Hummingbirds have the largest heart for their body size of any animals. This makes sure a rich supply of oxygen and nutrition are always flowing through the body. Hummers can allow their core body temperature to drop dramatically when asleep at night or sometimes during daytime naps. This conserves energy so they won't starve while they sleep. The body shape is close to spherical, helping the hummer to conserve energy, and fluffy body feathers hold the bird's body heat in. The tiny legs and feet simply cannot walk. They work just fine at clinging to thin twigs and branches. Hummingbirds are tiny enough to fit into tiny spaces even when their wings are spread in flight, and their unique ability to fly straight up, straight down, and backward makes walking unnecessary. Having tiny legs and feet improves their flight by making their bodies more streamlined and light. Hummingbirds eat a mostly liquid diet, so their bodies do not usually need to conserve water. Unlike all other birds, hummingbird urine is usually made up of the same clear, yellowish liquid, urea, that mammals produce. So it's hard to find "whitewash" anywhere around a hummer perch. (The urine produced by birds in other families is chalky and whitish because it's made up of uric acid, which helps them to conserve water.) Facebook Pinterest Twitter © 1997 – 2019 Journey North. All rights reserved.