Food resources from sperm whales

In the July 6 SN : Celebrating the 50th anniversary of Apollo 11, stone tool dates face scrutiny, ocean plastic goes deep, records of Inca taxation, erosion spurred plate tectonics and more. From the air, dwarf and pygmy sperm whales look similar. Their diets are similar, too, scientists have found. Though they inhabit wide ranges and depths of temperate and tropical oceans along continental shelves and slopes, they are rarely sighted. The pygmy species is a bit larger, and there are differences in morphology and genetics.

It is the only living member of the genus Physeter and one of three extant species in the sperm whale family , along with the pygmy sperm whale and dwarf sperm whale of the genus Kogia. The sperm whale is a pelagic mammal with a worldwide range, and will migrate seasonally for feeding and breeding. The females cooperate to protect and nurse their young. Females give birth every four to 20 years, and care for the calves for more than a decade. A mature sperm whale has few natural predators, although calves and weakened adults are sometimes killed by pods of killer whales orcas.

The consumption of marine mammal products is common in many cultures and countries. Additionally, marine mammals represent a significant aspect of food security, cultural well-being and economic benefits in 54 countries. It is widely accepted that the traditional Inuit diet consisting of mainly marine mammals, with relatively little fish, some game meat, and local berries prevented the effects of lifestyle diseases such as cardiovascular diseases, thrombosis and atherosclerosis. There are indications that consumption of marine mammals may be an important protective factor against prostate cancer, and that regular intake of seal and whale products give a lung functionality compatible with the level achieved when consuming vegetables and fruits on a daily basis.

Karen Evans, Mark A. Stomach contents were collected from 36 sperm whales Physeter macrocephalus involved in two mass stranding events during February along the west coastline of Tasmania, Australia. Contents were dominated by oceanic cephalopods, with a total of cephalopod beaks representing 48 species from 14 families of Teuthids, two species from two families of Octopods, and a single Vampyromorph species identified. Diet samples were dominated by subtropical and muscular cephalopod species.