I was trying to decide what to write about next and I started to think about what make birds unique. There are many interesting anatomical differences and similarities to mammals that most people don’t realize. Adaptations in anatomy allow birds to fly, migrate hundreds of miles, stay warm or cool in harsh environments, digest food that others may not be able to eat, talk and mimic like no other animal, and the list goes on.
So here are some interesting anatomical facts:
- Many birds have become asymmetrical to make them lighter and more efficient. For example, mammals have two jugular veins that allow blood to flow from the head back to the heart and they are about the same size on both sides of the neck. Most birds have a larger vessel on one side of the neck than the other–often it is the right side that has a more prominent vein. Many female birds also have a single oviduct or reproductive structure with one ovary. This is usually found on the left side of the body. Males do have two testicles though.
- Wings are amazing structures. Just like front leg/arms on a mammal, they have a humerus, radius and ulna (although the ulna is larger of the two bones in the bird which is opposite of humans), and a wrist joint and fingers or digits. Most of the wrist bones and bones that would be a hand are fused (carpals and metarcarapals) and they have three digits–the alular digit is similar to the mammalian thumb.
- Birds have airsacs throughout their bodies. Imagine balloons that fill up with air, then the air passes to the lungs, then to another air sac, then back to the lung–thus allowing air to pass twice through the lungs for more efficient filtering of oxygen. The airsacs also extend from the body into the the wings and legs (humeri and femurs) and this allows these bones to be hollow and lighter than those found in other animals.
- Birds do have ribs and they have a keel. Anyone who has eaten a bird or prepped a meal has seen the large breast plate that is under the “white meat” or breast muscle. It is this bone and these muscles that allow the bird to expand the chest to breath. Birds do not have a diaphragm and thus all of their organs are in one chamber with no division. This is why it is so important to restrain a bird properly. If you hold a bird two tight around the body and chest, they will not be able to breath.
- Birds have two parts to their stomachs. A simple stomach called the proventriculus which has gastric juices and fluids for enzymatic breakdown of food. They also have a gizzard or a ventriculus. This is a muscular structure that acts as a grinding organ to break down harder foods and seeds. Many people of pet birds assume they need to provide grit (tiny pebbles) daily for the birds so that the gizzard can use this to help grind down hard foods. Pet birds do not need a daily dose of grit. In fact they need little if any to help with normal grinding function of the gizzard. In fact, too much grit can lead to obstruction.
These are just a few of many differences. After getting this far, I figured I should post on this and then make additional posts for more fun facts…otherwise I can just keep going and never it it on my page. So stay tuned…