The term “shiver” is the collective noun used to describe a group of sharks, similar to how “pride” is used for lions or “pod” for dolphins. Though many people picture sharks as solitary hunters, they sometimes gather in groups large enough to be called a shiver. This grouping behavior, known to scientists as aggregation, is usually temporary and driven by specific biological or environmental factors.
Defining the Collective Noun and Its Origins
The word “shiver” is the accepted term for a group of sharks, though it is a colloquialism rather than a scientific designation. Its origin is not definitively known, but two main theories exist regarding its etymology. The first suggests the word refers to the sudden, uncontrollable trembling a person might feel when faced with the fear of multiple sharks in the water.
The second theory connects “shiver” to the Old English word “shive,” which means a slice or a shard. This interpretation relates to the way a shark appears to slice effortlessly through the water, suggesting a descriptive link to their sharp, fluid movements.
The Reality of Shark Aggregation
Despite the common term, most shark species, particularly larger ones like the Great White and Tiger shark, are generally solitary. Therefore, a true “shiver” is not a permanent social structure but a temporary gathering, or aggregation, occurring when certain conditions align. These aggregations are often non-social, meaning individuals are co-occurring due to a shared resource rather than a desire for social interaction.
Feeding Opportunities
One common reason for a shiver to form is the abundance of prey. When food sources like seasonal fish spawns or large bait balls appear, multiple sharks gather to feed. Great White sharks, for instance, are known to aggregate near seal colonies or whale carcasses, where they may establish dominance hierarchies.
Reproduction and Migration
Aggregation also occurs for reproductive purposes, such as during mating season, when males and females temporarily gather to find a mate. Furthermore, some species form large groups for migration, a behavior most notable in the Scalloped Hammerhead shark. These massive gatherings, sometimes numbering in the hundreds, are thought to aid in navigation or provide a safety-in-numbers advantage during long journeys.
Rest and Thermoregulation
Specific species of sharks also gather for rest and thermoregulation. For example, nurse sharks and Caribbean reef sharks have been observed grouping in certain environments, such as caves or specific resting spots, during the day.