Question 1

How do you say naris?

Accepted Answer

Naris is pronounced NAY-riss. The first syllable rhymes with the word day, and the second syllable is a soft hiss, like the word miss. The plural form, nares, is pronounced NAY-reez. You will hear paleontologists use both forms regularly when describing dinosaur skulls.

Question 2

What does naris mean?

Accepted Answer

Naris is the Latin word for a nostril. Scientists use it instead of the everyday word nostril because it is precise and works in both singular and plural forms, naris for one nostril and nares for both. The term has been used in anatomy since ancient Roman times and is still standard in zoology and paleontology today.

Question 3

Where were the nostrils on a T. rex?

Accepted Answer

Tyrannosaurus rex had a pair of external narial openings positioned toward the front of its snout, between the premaxilla bones at the tip and the nasal bones that ran along the top of the skull. The bony openings were relatively large. Research suggests the fleshy nostrils sat near the front edge of these bony openings, pointing somewhat forward and outward on the face, giving T. rex an excellent ability to draw in scent-laden air.

Question 4

Did dinosaurs have good noses?

Accepted Answer

Many dinosaurs had excellent senses of smell. Studies of fossilized braincases, particularly those of large theropods like Tyrannosaurus rex, show very large olfactory bulbs, the brain regions that process smell. A 2008 study led by researcher Darla Zelenitsky estimated that T. rex had one of the best senses of smell among all dinosaurs, comparable to a modern turkey vulture. The nares were the starting point for all that sensory information entering the body.

Question 5

Why did some dinosaurs have such big nasal openings?

Accepted Answer

The size of the bony narial opening does not directly equal nostril size in life. Some dinosaurs, like ceratopsians and hadrosaurs, had very large bony narial regions that may have housed extensive soft-tissue structures such as inflatable display pouches or resonating chambers. In hadrosaurs with crests, the nasal passages were looped and enlarged for possible sound production. Scientists are still working out exactly why some lineages evolved such dramatically enlarged nasal regions.

Question 6

What is the difference between naris and nares?

Accepted Answer

Naris is the singular form, meaning one nostril. Nares is the plural form, meaning both nostrils or the nostrils collectively. In practice, when paleontologists describe a skull they will often say the external nares to refer to the paired openings on both sides of the snout. Both words come from the same Latin root and have been used in scientific writing for several centuries.

Question 7

Did Brachiosaurus really have nostrils on top of its head?

Accepted Answer

For a long time scientists believed so, because the bony narial opening in Brachiosaurus sits high on the skull above the eyes. This led to the old theory that sauropods lived mostly in water with just their nostrils poking above the surface. However, paleontologist Lawrence Witmer published a study in 2001 in the journal Science showing that in all living relatives of dinosaurs, the fleshy nostril sits near the front of the bony narial opening. This means the actual nostrils of Brachiosaurus were probably positioned much further forward on the snout, not on top of the head.

Question 8

What are internal nares?

Accepted Answer

Internal nares, also called choanae, are the openings at the back of the nasal passage where it connects to the throat. While external nares are the visible nostrils on the outside of the face, internal nares are the exit points on the roof of the mouth. In crocodilians, the internal nares are positioned far at the back of the palate, which lets the animal breathe even when its mouth is full of water or prey. Some dinosaurs appear to have had similarly positioned internal nares, which may have been useful for eating large prey.

Question 9

How do paleontologists find the narial opening in a fossil skull?

Accepted Answer

The external narial opening shows up in a fossil skull as a clearly defined gap or hole in the bones of the snout, typically framed by the premaxilla at the front and the nasal bones along the top. It is one of the most reliably identifiable openings in any dinosaur skull and is used as a key reference point when describing skull anatomy. Paleontologists measure its length, width, and position relative to other skull features to compare species and understand evolutionary trends.

Question 10

Did all dinosaurs have two nostrils?

Accepted Answer

Yes, all dinosaurs had paired narial openings, one on each side of the snout, just like all other vertebrates with nostrils. However, in many dinosaur skulls the two bony narial openings are positioned so close together and blend into such a large single cavity on the skull roof that they can appear to form one large opening. This is especially true in sauropods and some theropods. In life, the soft tissue would have divided this space into two distinct nostrils.

Question 11

What is a narial crest?

Accepted Answer

Some dinosaurs had bony crests or ridges surrounding or growing near the narial opening, which scientists call narial crests. Theropods in the family Proceratosauridae, which includes relatives of Tyrannosaurus, had elaborate nasal crests that grew directly over or around the narial region of the skull. These were likely used for display to impress mates or intimidate rivals. The crests were made of thin bone and would have been brightly colored in life, according to many researchers.

Question 12

Can you tell what a dinosaur smelled like from its naris?

Accepted Answer

Not exactly, but the size and shape of the narial opening gives scientists clues about olfactory ability. A larger narial region often corresponds to more extensive nasal tissue and potentially a better sense of smell. Studies using endocasts, casts of the inside of the braincase, can measure the olfactory bulbs directly. Research published by Darla Zelenitsky and colleagues in 2011 in the journal Proceedings of the Royal Society B ranked the smelling ability of various dinosaur groups based on these measurements, with large theropods coming out near the top.

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