The bull shark, Carcharhinus leucas, is known for its ability to inhabit both saltwater and freshwater environments. For collectors and enthusiasts, identifying the teeth of this versatile predator is straightforward once certain characteristic features are understood.
Overall Shape and Dimensions
A bull shark tooth is identified by its distinctive broad, triangular architecture, giving it a stocky, robust appearance. Specifically, the tooth crown typically features a width-to-height ratio near 1:1 or 1.2:1, making it wider at the base than it is tall. This creates a significantly broader profile compared to the more elongated teeth of a Great White shark.
Adult bull shark teeth generally measure between 0.8 and 1.5 inches in length. Juvenile teeth are often smaller, ranging from 0.5 to 0.8 inches. When teeth are found fossilized, their coloration can range from gray and tan to jet black, depending on the minerals in the sediment where they were preserved.
The Serration Pattern and Root Structure
The cutting edges of a bull shark tooth are lined with prominent, coarse serrations that run completely from the root base to the apex. These serrations are often described as “chunky” or irregular, appearing larger and more pronounced than the fine serrations found on other related shark species, such as the lemon shark.
The tooth’s base, known as the root, is thick, heavy, and robust, forming a wide foundation for the broad crown. This substantial root structure is V-shaped with well-developed lateral lobes, providing the necessary anchoring to withstand the shark’s powerful bite force. Unlike the teeth of some other sharks, bull shark teeth lack distinct cusplets.
Functional Variation: Upper Versus Lower Jaw Teeth
Bull sharks display heterodonty, meaning the teeth in their upper jaw differ significantly in shape and function from those in their lower jaw. The teeth from the upper jaw are the ones most commonly recognized, featuring the classic broad, triangular shape and heavy serration designed for cutting and slicing. These upper teeth are crucial for severing large pieces of flesh.
In contrast, the lower teeth are much narrower, more pointed, and straighter, often described as blade-like or slender. These lower teeth serve a different purpose, functioning primarily to grip and secure the prey while the upper teeth perform the cutting. Recognizing whether a tooth is broad and triangular (upper) or narrow and pointed (lower) is necessary for full identification.