Philatelic document - Nature - Cetaceans

Cetaceans Mythical and little-known: while cetology has made great strides since Aristotle, who noted that cetaceans have lungs and reproduce like mammals, cetaceans remain mysterious because, spending their entire lives at sea, they are usually invisible on the surface and rarely seen near shore. Cetaceans comprise two suborders: mysticetes, or baleen whales, and odontocetes, or toothed whales. Of the latter, the delphinid family comprises 37 species, from the orca to the southern bottlenose dolphin. Killer whales are found in almost all the world's seas; this large predator lives in matriarchal groups and feeds on a wide variety of prey, from herring to whales. The sperm whale, Herman Melville's Moby Dick, is the largest of the odontocetes: males measure up to 18 meters. They dive to depths of over 1,000 meters to capture their favorite prey, squid, which can exceed 3 meters in length. They are remarkable for their social life, organized around groups of females, who are smaller than the males. Also highly social, belugas are opportunistic predators. Also known as white whales, these 5-meter odontocetes live in the Arctic seas, including near pack ice... hence their color! Belugas have no dorsal fin, like their narwhal cousins. The mysticete suborder comprises 15 species, the best-known being the humpback whale: this whale, which feeds on small fish or crustaceans, breeds in the waters of tropical archipelagos, not far from the coast, where it is much admired by the public. The megaptera, its other name due to its large pectoral fins, is also famous for its songs. Still sometimes hunted, cetaceans are facing a galloping industrialization of the marine environment. However, humpback whales, belugas, sperm whales and orcas are not among the species directly threatened with extinction.

Bloc de timbres-poste (héliogravure) : création Mathilde Laurent d'après photos © Pierre Lobel / Biosphoto, © Andrey Nekrasov / imageBROKER / Biosphoto, © Gérard Lacz / Biosphoto, © Reinhard Dirscherl / Biosphoto. Document philatélique : création Mathilde Laurent. Cachet d'oblitération : création Mathilde Laurent. Texte : Alexandre Gannier.