Lemon Sharks (Negaprion brevirostris): a Close Look at the Species

Are lemon sharks dangerous to humans?

Lemon sharks represent a minimal threat to humans. According to the International Shark Attack File, there were only ten unprovoked attacks of lemon sharks (all in Florida and the Caribbean Islands), and none ended fatally. The lemon shark inhabits coastal waters and often lives close to swimmers, surfers and divers but does not attack if not provoked. The number of attacks by species is low, but we advise you to remain cautious as they are a large predatory species (ISAF 2018).

Given that the lemon shark is a target for commercial (meat and leather) and recreational fishing throughout its range and its place on the IUCN Red List as Near Threatened, we can say that humans are much more dangerous to this shark than it is to humans.

Skills and diet

The lemon shark’s yellow skin colour provides perfect camouflage in sandy in-shore areas where it often forages for food. The colour, flattened head, and short snout make the lemon shark a skilful predator of bony fish, crustaceans and stingrays. Occasionally, it can eat seabirds or even smaller sharks. Often feeding at night, these sharks use electroreception to detect electrical pulses emitted by potential prey. The retina in their eyes has a “visual streak” (a specialized horizontal band), which allows them to see fine detail and colour underwater.

Life and social behaviour

Though lemon sharks prefer shallow coastal waters, some individuals are entering freshwater or undergoing migrations through the open ocean. Still, lemon sharks prefer a defined home range and may congregate in groups of up to 20 individuals to feed together overnight. During the day, lemon sharks often rest on the seabed waiting for small fish to clean off parasites from their body. However, this behaviour takes up more energy than swimming as the shark must continually pump water over its gills to breathe.

Lemon sharks create groups based on the similarity of sizes. The passive sorting mechanisms, such as ontogenetic habitat change, contribute to the formation of groups based on size or sex. One exception to this behaviour is sharks younger than one year showing no grouping preference. It is advantageous for small, juvenile lemon sharks to stay with older individuals because they can more easily learn from them and gather habitat information about elements such as predators and local prey. Groups of lemon sharks form because of an active desire to be social rather than simple protection reasons or attraction to the same limited resources. Many studies have linked brain size to complex social behaviour in mammals and birds. The brain of the lemon shark, being comparable in relative mass to that of a mammal or bird, suggests that they can learn from social interactions, cooperate with other individuals and have the potential to establish dominance hierarchies and stable social bonds.