are crocodiles more related to lizards or birds

The Missing Link For centuries, many scientists hypothesized that birds were reptiles due to similarities in their anatomy, but there was no hard fossil evidence to support it. But in 1860, archaeologists discovered a fossil of a highly detailed Archaropteryx lithographica (a bird-like dinosaur), which filled the void of the “transitional species” that scientists needed to link birds and reptiles. Since then, many fossils of feathered dinosaurs have been found.

are crocodiles more related to lizards or birds

How Birds and Reptiles are Related

We specialize in reptiles and amphibians here at the zoo, and that includes emus and parakeet exhibits. As a result, we frequently receive feedback from guests who question why, exactly, there are birds at a reptile zoo. The short answer is that birds are reptiles, but it wasn’t always so. Let us explain.

Reptiles today can be divided into four main categories: dinosaurs, crocodilians, lizards and snakes, and turtles and tortoises. The final two groups are the living reptiles most closely related to birds, the archosaurs, a highly specialized group of reptiles that have existed for 225 million years.

Here’s a more thorough explanation from Ask a Biologist at Arizona State University: The closest living relative of birds is the crocodile. To understand this, we should look at some history. Reptiles diverged into their first groups approximately 300 million years ago. After roughly 40 million years, or very quickly by geologic standards, a branch of reptiles known as therapsids split off, giving rise to modern mammals. Over the course of the next 120 million years, other groups of reptiles split off, with one branch known as the dinosaurs becoming extremely successful. Only distantly related to modern snakes, lizards, and turtles—groups that split off at different times—were these dinosaurs. However, a massive extinction event occurred 65 million years ago, eradicating all dinosaurs save for a small group of feathered dinosaurs. Over the following 65 million years, these gave rise to modern birds. Thus, birds are actually dinosaurs, not just distant relatives of them!

For the avian phylogenetic analyses, the crocodilian genomes were also helpful because they provided a closely related “out group” to compare with the bird genomes. Alongside the Science paper on crocodile genomics, Green and a number of other UC Santa Cruz researchers are coauthors of two articles on avian genomics.

Richard E. The slow rate of evolution in the crocodilian lineage was useful in reconstructing the genome of the common ancestor, according to Ed Green, lead author of the crocodilian genome paper and assistant professor of biomolecular engineering at UC Santa Cruz.

“We can see back into their past more cleanly because the crocodilians’ molecular clock ticks off much slower than other lineages we are accustomed to seeing, like mammals,” explained Green.

An invaluable resource for examining the evolution of the “archosaurs,” which comprise all dinosaurs, pterosaurs, birds, and crocodilians, will be the reconstructed genome of the common ancestor. In actuality, Crocodilians are more closely related to dinosaurs and birds than they are to other reptiles. e. , lizards, snakes, and turtles. According to Green, the UC Santa Cruz research specialist Benedict Paten led the genome reconstruction effort, which produced roughly half of the common ancestor’s genome sequence with an accuracy of roughly 91%. He anticipates that this will improve as more information on the genomes of birds and crocodiles becomes available.

According to him, the recently released genome sequences are excellent resources for studying the basic biology of alligators and crocodiles. The molecular underpinnings of alligators’ temperature-dependent sex determination, which determines an alligator’s gender based on development rather than heredity, are of special interest to Green. “With genomics, we can now begin to address many of the questions regarding the evolutionary and molecular biology of crocodilians,” he stated.


What animal is most closely related to crocodiles?

The researchers found that turtles are most closely related to crocodiles, and least similar to snakes and lizards.

Are crocodiles more closely related to lizards or to birds explain your response?

Yes, crocodiles are indeed closer to birds than to lizards and for that matter any other group of reptile alive today. As shown in the diagram below, crocodiles and birds are both members of the clade Archosauria, while lepidosaurs, which include lizards, iguanas and snakes, are a distinct lineage.

Are Crocs related to lizards?

No. Alligators, crocodiles, caimans, and gharials are all crocodilians. Like lizards, they’re generally considered to be reptiles. However, they’re not very closely related to lizards, as reptiles go.

Are birds the closest relatives to crocodiles?

It may seem hard to find two animals more different than a hummingbird and an crocodile But as strange as it may be, birds and crocodilians (the group containing alligators, crocodiles and gharials) are each other’s closest relatives.