Marine Mammals

  Abundance estimation covers the range of techniques by  which the size of a population of marine mammals can be estimated. Such population size estimates are often referred to as “absolute” abundance estimates. When it is difficult to estimate absolute abundance with an acceptably low bias, relative abundance indices are often used instead. These are […]

Age Estimation (marine mammals)

  Age estimation is a tool for obtaining a numerical value of age for animals for which actual age is not known. Currently, age is estimated primarily from counts of growth layers deposited in several persistent tissues, primarily teeth, less often bone, and in some cases from other layered structures or from chemical signals. Growth […]

Aggressive Behavior (Intraspecific) (marine mammals)

    The heterogeneous phenomenon considered as intraspecific aggressive or agonistic behavior represents a conglomerate of social responses, including male disputes over territorial boundaries, female fights to protect an offspring, female harassment and forced copulations, and infant abuse and killing. Agonistic encounters: 1. Mediate competition for limited resources economically defendable and valuable to the fitness […]

Amazon River Dolphin (marine mammals)

    I. Genus and Species: Common Names and Taxonomy The Amazon River dolphin. Inia geoffrensis, is known by different names throughout its distribution: boto in Brazil; bufeo and bufeo Colorado in Colombia, Ecuador, and Peru; and tonina and delfin rosado in Venezuela. It is also known in English as pink dolphin, although the Brazilian […]

Albinism (marine mammals)

  Albinism refers to a group of inherited conditions resulting in little or no pigment (hypopigmentation) in the eyes alone or in the eyes, skin, and hair. In humans, all types of albinism exhibit abnormalities in the optic system, including misrouting of the optic fibers between the retina and the brain, and incomplete development of […]

Ambergris (marine mammals)

    Ambergris is a substance that forms only in the intestines of the sperm whale (Physeter macrocephalus). The word comes from the Old French ambre gris or “gray amber,” as opposed to ambre jaune, “yellow amber,” which refers to the true, resinous amber. Most ambergris is found in the large intestine, but smaller pieces […]

Anatomical Dissection: Thorax and Abdomen (marine mammals)

  The general organization of the postcranial soft tissues does not vary appreciably among mammals. Factors that may influence the relative proportions or positions of organs and organ systems include phylogeny and adaptations to a particular environment or trophic level. This article provides a “road map” that orients a prosector to the organs and organ […]

Antarctic Marine Mammals

    The Southern Ocean is the oceanic region surrounding the continent of Antarctica. Its southern boundary is defined by the narrow coastal continental shelf of Antarctica itself. To the north the boundary is defined by an oceanic frontal feature known as the Antarctic convergence or southern polar frontal zone. This zone marks the boundary […]

Archaeocetes, Archaic (marine mammals)

  Archaeocetes is the common name for a group of primitive whales that lived in the Eocene Period (approximately 55-34 million years ago). Archaeocetes are important because they represent the earliest radiation of cetaceans and because they include the ancestors of the two modern suborders of cetaceans (Mysticeti and Odontoceti), Archaeocetes are also the main […]

Artiodactyla (marine mammals)

    Artiodactyls are the closest living relatives of the Cetacea (whales and dolphins), although whales may be more closely related to an extinct group of mammals, the mesonychids. It seems odd to think of the whales being closely related to terrestrial ungulates, but biologists have long appreciated that artiodactyls and whales share several unusual […]