Dolphin Teeth: Everything You Need to Know
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Dolphins live in all of the world's oceans, and even in some of the largest freshwater rivers. Like whales, they are considered cetaceans — mammals that inhabit the oceans. There are four main families of dolphins with 40 extant (extant) species. Of these 40 species of dolphins, 30 belong to the family Delphinidae. Three other families (Iniidae, Pontoporidae, and Platanistidae) include the world's river-dwelling dolphins. Dolphins are mammals that eat meat and have teeth.
Here, we'll learn all about dolphin dentition. Every dolphin is unique, but they all follow the same general rules when it comes to their dentition. We'll explore the normal number of teeth in dolphins, and what's special about dolphin teeth. We'll then delve into several unique species with special mouths (dolphins) and discuss how scientists can determine the age of dolphins based on their teeth.
How many teeth do dolphins have?
Dolphins evolved from land creatures millions of years ago. As they adapted to life in the sea, they also developed far more teeth than their terrestrial ancestors. Because dolphins have more than 44 teeth per quadrant of their mouth (think top, bottom, left, and right), they're called polydentates. Polyodonty means "many teeth," and dolphins certainly live up to their name.
Let's take a look at the teeth of some of the most common dolphin species.
- Short-beaked dolphin (Delphinus delphis): 160-228
- Long-beaked dolphin (Delphinus capensis): 188-268
- Bottlenose dolphin (Tursiops truncatus): 72-116
- Spinner dolphin (Stenella longirostris): 180-260
- Pacific white dolphin (Lagenorhynchus obliquidens): 92-144
What type of teeth do dolphins have?
Dolphins are odontocetes, meaning toothed cetaceans. They share features with other cetaceans such as sperm whales, beaked whales and porpoises. The largest member of the dolphin family is the orca (Orcinus orca). It may be huge, but even orcas, also known as killer whales, have the same dentition as the much smaller bottlenose dolphins.
Almost all dolphin species are synodonts, meaning they have only one type of tooth. In comparison; humans have four different types of teeth – incisors, canines, premolars and molars. A dolphin's only tooth type is small (up to ½ inch) and conical in shape. Depending on the dolphin species, these teeth may be blunt or sharp – it all depends on what they like to eat.
diet and teeth
Dolphins mainly eat fish, krill, plankton and cephalopods (squid). But different species of dolphins may eat more of one species than the other; this is where the differences in teeth emerge. Some species, such as the bottlenose dolphin, typically feed on fish, squid, and krill, and have very characteristic conical cogs. While other species, such as orcas, primarily eat large prey such as seals, and have sharper teeth to tear through flesh. There are other species of dolphins that have more specialized dentitions due to their unique diets – more on that later.
Dolphins don't just use their pearly whites to catch fish; they use them to establish dominance over other dolphins. Dolphins are social animals, living in colonies of up to dozens of animals. Each group has a unique social hierarchy, starting with the lowest-ranking (usually youngest) individual and moving up to the most dominant member of the group.
One of the tools dolphins use to establish dominance is a behavior called "rake." Ragging occurs when a dolphin scrapes against the body or face of another member of the pod with its front (front) teeth. This leaves a series of shallow incisions in the other dolphin's skin. They're not life-threatening, but the teeth seem to be sending a message: maintain order and respect hierarchy.
Do all dolphins have teeth?
All dolphins have teeth. Most of them have many teeth (over 150), but one species (the Risso dolphin) has fewer than 20 teeth in its entire mouth. Additionally, the teeth of Riso's dolphins and Amazon river dolphins are a bit more complex than those of common cetaceans.
Riso dolphins ( Grampus griseus ) live in temperate and tropical oceans around the world. They probably have the most specialized dentition as they have no upper teeth and only 4-14 teeth in the lower jaw. Their teeth are located at the very front of the mouth and are much sharper than typical dolphins. Riso dolphins have this special dentition because they eat almost exclusively squid.
amazon puffer fish
The Amazon river dolphin ( Inia geoffrensis ) lives in the freshwater of the Amazon and Orinoco river basins. Known for their pink color, they feed on fish, turtles and crabs. Because they ate harder foods like crabs and turtles, they grew flatter molar-like teeth in the back of their mouths. These dolphins are technically considered heterodonts — meaning they have more than one type of tooth.
Judging a dolphin's age from its teeth
Dolphin pups feed on their mother's milk for the first few months of their lives. Once they are about three months old, their teeth will begin to erupt. By the time they are six months old, they have all their adult teeth. Dolphins are monovertebrates, meaning they have only one set of pearly whites throughout their lives.
As dolphins age, their teeth grow in layers like a tree. With each passing year, dolphins grow a layer of dental material. In the case of a necropsy (a medical examination of a deceased dolphin), scientists can use these layers to determine the exact age of the dolphin.
Dolphins also experience tooth wear as they age. This is especially noticeable in the front teeth which are used the most. As the teeth wear down, they become blunter, rounder and may eventually become stubby. Dolphins don't grow teeth; once their teeth wear down, they don't come back.
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about the author
Brandi is a professional writer by day and a fiction writer by night. Her nonfiction work focuses on animals, nature, and conservation. She has degrees in English and Anthropology and writes horror, science fiction and fantasy stories in her spare time.
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