Cetology in the context of "Porpoises"

Whales use a variety of sounds for communication and sensation. The mechanisms used to produce sound vary from one family of cetaceans to another. Marine mammals, including whales, dolphins, and porpoises, are much more dependent on sound than land mammals due to the limited effectiveness of other senses in water. Sight is less effective for marine mammals because of the way particulates in the ocean scatter light. Smell is also limited, as molecules diffuse more slowly in water than in air, which makes smelling less effective. However, the speed of sound is roughly three times greater in water than in the atmosphere at sea level. As sea mammals are so dependent on hearing to communicate and feed, environmentalists and cetologists are concerned that they are being harmed by the increased ambient noise in the world's oceans caused by ships, sonar and marine seismic surveys.

The word "song" is used to describe the pattern of regular and predictable sounds made by some species of whales, notably the humpback whale. This is included with or in comparison with music, and male humpback whales have been described as "inveterate composers" of songs that are "'strikingly similar' to human musical traditions". This position has been complicated by more recent research, however. It has been suggested that humpback songs communicate male fitness to female whales, although this explanation has been challenged on various grounds.

In zoology, mammalogy, from Latin mamma, meaning "breast", and -logy from λόγος (lógos), meaning "study", is the study of mammals – a class of vertebrates with characteristics such as homeothermic metabolism, fur, four-chambered hearts, and complex nervous systems. The archive of the number of mammals on earth is constantly growing, but is currently set at 6,495 different mammal species including recently extinct. There are 5,416 living mammals identified on earth and roughly 1,251 have been newly discovered since 2006. The major branches of mammalogy include natural history, taxonomy and systematics, anatomy and physiology, ethology, ecology, and management and control. Mammalogists are typically involved in activities such as conducting research, managing personnel, and writing proposals.

Mammalogy branches off into other taxonomically oriented disciplines such as primatology (the study of primates), and cetology (the study of cetaceans). Like other studies, mammalogy is also a part of zoology which is also a part of biology, the study of all living things.

The International Whaling Commission (IWC) is a specialised regional fishery management organisation, established under the terms of the 1946 International Convention for the Regulation of Whaling (ICRW) to "provide for the proper conservation of whale stocks and thus make possible the orderly development of the whaling industry".

As the decision-making body of the convention, the IWC reviews and revises measures laid down in the "Schedule to the Convention", which govern the conduct of whaling throughout the world. These measures include: confer complete protection of certain species; designate specific areas as whale sanctuaries; set limits on the numbers and size of whales which may be taken; prescribe open and closed seasons and areas for whaling; and prohibit the capture of suckling calves and female whales accompanied by calves. The Commission also mandates the compilation of catch reports and other statistical and biological records, and is actively involved in whale research, including funding and promoting studies, publishing the results of scientific research, and encouraging studies into related matters, such as the humaneness of the killing operations.

In cetology, the study of whales and other cetaceans, a blowhole is the hole (or spiracle) at the top of the head through which the animal breathes air. In baleen whales, these are in pairs. It is homologous with the nostril of other mammals, and evolved via gradual movement of the nostrils to the top of the head. The posterior placement of blowholes on cetacean heads is believed to minimize the energy used when breathing at the water's surface.