Marine mammals represent a fairly varied group of species that includes whales, dolphins, seals and sea lions. They share common features with terrestrial mammals, aerial respiration, body temperature regulation and viviparous reproduction, while exhibiting specific adaptations to life in aquatics.
Characteristics of marine mammals
Marine mammals are distinguished by several remarkable morphological and physiological adaptations. Their bodies are often spindle-shaped, minimizing resistance to friction in water. Their front limbs have transformed into flippers and, in some cases, the hind limbs have disappeared or are still present only as vestige. Their skin is generally smooth. Their bodies are also covered in a layer of insulating fat, essential for retaining body heat. Their circulatory system is adapted to deep dives, allowing optimal use of oxygen and resistance to the pressure of great depths.
Marine mammal habitat
Marine mammals inhabit a variety of spaces, from shallow coastal waters to the abyssal depths of the oceans. Certain species, such as seals, also frequent the poles. Their geographic distribution is actually influenced by food availability, environmental conditions and ocean currents. Migrations are common among these animals, often linked to breeding seasons or the search for rich feeding areas.
Marine mammal diet
The diet of marine mammals varies depending on the species. Baleen whales, for example, filter feed on seawater, consuming large quantities of krill and small fish, while dolphins and orcas actively hunt specific prey. Seals and sea lions feed on a variety of fish and marine invertebrates. The ability to locate food in the darkness of the depths or in murky waters is facilitated by highly developed senses, including echolocation in dolphins.
Reproduction of marine mammals
Most species have a long gestation, followed by the birth of a single young that is usually well developed and capable of swimming shortly after birth. Bonds between mother and calf are often strong, with an extended period of breastfeeding during which the calf learns the skills necessary for survival. Some species form long-lasting pair bonds, while others exhibit polygamous behavior.
Conservation status of marine mammals
The conservation status of these marine mammals varies considerably depending on the species. According to the International Union for Conservation of Nature (IUCN), some of them are classified as threatened with extinction or critically endangered, mainly due to hunting, loss of habitat, collisions with ships, fishing nets, and climate change which affects the availability of their food. Conservation efforts include the creation of marine protected areas, fishing regulations, and awareness campaigns aimed at reducing marine pollution.
International initiatives, such as the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) and the Agreement on the Conservation of Cetaceans of the Black Sea, the Mediterranean and the Adjacent Atlantic Area (ACCOBAMS), play a key role in the protection of these animals.