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Shark migration patterns may be even more complex than in birds, with many sharks covering entire ocean basins. Sharks can be highly social, remaining in large schools. Sometimes more than 100 scalloped hammerheads congregate around seamounts and islands, e.g., in the Gulf of California. [39] Cross-species social hierarchies exist.
Off KwaZulu-Natal, the decimation of large sharks by the use of gillnets to protect beaches has led to a recent increase in milk shark numbers. [17] A known parasite of this species is the copepod Pseudopandarus australis. [18] There is some evidence that male and female milk sharks segregate from each other. [14]
Shark Anatomy (50693674756) The gill slits of a whale shark flaring as it expels water from its pharyngeal cavity. In the shark anatomy image, it depicts the beginning half of the shark, including the gills. The shark gills are especially important and were evolved from the chordate pharyngeal gill slits synapomorphy.
The following outline is provided as an overview of and topical guide to sharks: Sharks (superorder Selachimorpha) are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 440 million years ago, before the time of the dinosaurs. [1]
The first shark-like chondrichthyans appeared in the oceans 400 million years ago, [1] developing into the crown group of sharks by the Early Jurassic. [2] Listed below are extant species of shark. Sharks are spread across 512 described and 23 undescribed species in eight orders. The families and genera within the orders are listed in ...
Of 548 known shark species, ... Researchers with SeaWorld say sharks only eat anywhere between 1% and 10% of their ... Instead of swearing off the ocean, he went on to study sharks intently, ...
Argos system satellite tagging of 20 basking sharks in 2003 confirmed basking sharks move thousands of kilometres during the summer and winter, seeking the richest zooplankton patches, often along ocean fronts. [7] [31] They shed and renew their gill rakers in an ongoing process, rather than over one short period. [32]
In the last six years, we've even seen the occasional fin pass by in the ocean and played in shallow waters where we've had to take pause while a herd of nurse sharks passed by (unnerving, yes ...