Bones one method to ID animals

October is when many people think about skeletons and ghoulish creatures. Rather than focusing on the scary side of these things, why not take a closer look at what is inside the animals found all around us?

Birds, mammals, reptiles, amphibians and more are all classified as animals with backbones. Known as vertebrates, they also all have a skeleton attached to that backbone, but there is a great deal of variability in how that skeleton might occur.

Let’s first look at the one inside-structure that is used the most often for identification purposes by scientists and nature lovers. The skull, made up of a series of bones fused together is distinctive for every group of vertebrates.

For example, with mammals, it is fairly easy to see what an animal eats based on the skull. You just need to look at the teeth. Carnivores are meat eaters. Their skulls are made up of mostly sharp tearing teeth such as the incisors and canines. They do not have many flat grinding teeth like molars. Examples of local carnivores are bobcat, weasel and river otter.

Herbivores eat only plants and their skulls usually have many molars that work well for grinding up the plant materials. There are herbivores – such as mice, squirrels, deer, cows and horses – all around us.

Omnivores, like humans, are designed to eat both plants and meat so they have both sharp tearing teeth and flat grinding teeth. Since omnivores have many choices when it comes to food, they are often the most successful animals. Besides humans, other local omnivores include raccoons, foxes, coyotes and bears.

Other bones can help determine the species of an animal. Just like what is shown in the many crime procedures on TV, scientists can often determine the species of animal, its age, sex and how healthy it was. Some bones like the skull and leg bones are best for this, but if there is DNA present, any bone can work. There are even crimes and other mysteries that have been solved by getting important information from what animals have left behind when they die.

Usually, we don’t have much need for finding out all this detail, but it can be interesting to look at bones close up to see some of the amazing structures found in nature.

For example, if you have the chance to look close-up at a turtle shell, you will see that the turtle’s backbone is fused right into the inside top of the shell. That means the turtle can never leave the shell – it is part of its body.

Animals that have a strong bite have extra structures on the skull for extra muscle attachment. Have you ever felt a bump on the top of your dog’s head that seemed to get bigger as the dog got older? That bump is one of the ways a scientist can tell how old a wolf or coyote was when it died. All dog family members get a larger “bump” as they get older.

Vertebrates that are really flexible still have a skeleton, but it is made up of many smaller bones. For example, snakes have 100-300 vertebrae in their spine. Compare that to the 32-34 in humans. This allows a snake to have a great deal of flexibility. Humans and other larger animals , such as elk and elephants, need more strength in a spine to hold the body up, so the spine is made of fewer very strong and blocky vertebrae.

Truly one of the most amazing skeletal structures in the animal kingdom belongs to the birds. Their bones are incredibly light compared to the average vertebrate. They are almost completely hollow and are supported by a series of cross struts to retain strength while staying lightweight. Combined with strong chest muscles and feathers, these lightweight bones allow birds to fly. The types of birds that are not able to fly, like ostriches and emus, have bones much more like mammals.