What Can We Learn From Dinosaur Bones?
The giant dinosaurs disappeared millions of years ago, but their fossilized bones preserve clues about how they lived, moved, ate, and interacted with their environment.
Surprisingly, many of the bones in a T-Rex skeleton have counterparts in our own bodies. By examining the skull, vertebrae, ribs, arms, legs, and feet of T-Rex, we can better understand both dinosaur anatomy and how paleontologists reconstruct the lives of extinct animals.
Inside the Skull of T-Rex
A dinosaur skull isn't a single bone. It's made up of many individual bones that together provide important clues about how the animal ate and experienced the world around it.
The openings at the front of a T-Rex skull are the nares, where the nostrils were located, while the orbits housed the eyes. The skull also contains several openings called fenestrae, a characteristic feature of dinosaur skull anatomy.
At the back of the skull is the occipital condyle, which connected the skull to the vertebral column.
Teeth Built for a Powerful Predator
T-Rex had some remarkable teeth.
Each tooth consisted of a root held within the jaw and a visible crown. Unlike the flatter, blade-like teeth of many other meat-eating dinosaurs, T-Rex teeth were thick and robust, allowing them to withstand tremendous forces and crush through bone.
Along the edges were serrations called denticles, which helped the teeth cut through flesh.
T-Rex also continually replaced its teeth throughout its lifetime, much like modern crocodilians and sharks replace theirs today.
From Neck to Tail
The backbone of T-Rex was composed of individual bones called vertebrae, but different parts of the spine had different names and functions.
Cervical vertebrae formed the neck, dorsal vertebrae made up the back, sacral vertebrae connected with the pelvis, and caudal vertebrae extended through the tail.
The shape and structure of these bones can reveal important information about an animal's posture and flexibility.
Ribs and Belly Ribs
Like us, dinosaurs had ribs connected to their vertebrae, but their skeletal anatomy also included something humans don't have.
Many dinosaurs possessed gastralia, sometimes called belly ribs. These bones weren't directly attached to the spine like ordinary ribs. In dinosaurs, gastralia may have played a role in respiration.
T-Rex Arms Weren't So Different From Ours
T-Rex may be famous for its tiny arms, but the bones inside them are surprisingly familiar.
Like your arm, a T-Rex forelimb contained a humerus in the upper arm and a radius and ulna in the forearm, followed by wrist and finger bones.
There was one important difference in how T-Rex held those arms. Its palms would have faced inward toward one another rather than downward in the classic “bunny hands” pose sometimes seen in older dinosaur reconstructions.
A good way to picture the position is to imagine holding a basketball between your hands.
Legs Built to Carry a Giant
The hind limbs of T-Rex also contain bones familiar to us.
The massive upper leg bone is the femur. Below it are the tibia and fibula, followed by the ankle and foot bones.
The three primary toes contacted the ground and supported the dinosaur's weight, while another toe was smaller and raised above the ground. A fifth digit had become greatly reduced over the course of evolution.
Dinosaurs Walked on Their Toes
One of the biggest differences between the way humans and dinosaurs walked is easy to overlook.
Humans are plantigrade, meaning we walk with the soles of our feet on the ground. Dinosaurs like T-Rex were digitigrade, meaning they walked primarily on their toes.
So despite their enormous size and fearsome appearance, you could think of dinosaurs as walking a little like giant prehistoric ballerinas!
What Bones Can Tell Us
A dinosaur skeleton is much more than a collection of fossilized bones.
The size, shape, arrangement, and number of those bones can help paleontologists identify different species and investigate how extinct animals moved. Limbs, shoulders, hips, vertebrae, and other skeletal structures all preserve evidence that helps scientists reconstruct animals that disappeared millions of years ago.
Watch the full video below to explore the skeletal anatomy of T-Rex!
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