Southern Right Whale

This massive baleen whale is distinguished by its extremely robust, rotund body and the complete absence of a dorsal fin along its broad back. The skin of this marine giant is predominantly black or dark gray, often featuring variable white patches on the ventral area. Its most outstanding anatomical feature is the presence of thickened epidermal callosities on the head, which are colonized by dense populations of small amphipod crustaceans known as whale lice or cyamids. These keratinized formations present a unique distribution pattern for each individual, serving as a natural fingerprint that facilitates photo-identification by research teams. Adult specimens reach lengths of 15 to 18 meters and weigh between 40 and 80 metric tons, with females being slightly larger than males. The head accounts for nearly one-third of the total body length and houses a massive arched mouth containing 230 to 270 long, dark baleen plates on each side. When breathing, the whale exhales through two widely separated blowholes, creating a highly diagnostic V-shaped blow that can reach up to five meters in height and is visible from great distances.

Geographical distribution: It occupies a continuous circumpolar band across the Southern Hemisphere, ranging approximately between 20° S and 65° S latitudes. During the winter and spring seasons, populations migrate to low-latitude, temperate waters to mate and calve, concentrating in key coastal areas such as Península Valdés in Argentina, the coast of Santa Catarina in Brazil, the coastal waters of South Africa (particularly Hermanus), the bays of southern Australia, and the sub-Antarctic waters of New Zealand (including the Auckland Islands). In the summer, they undertake a massive migration toward the nutrient-rich, cold waters of the sub-Antarctic and Antarctic oceans to exploit high concentrations of food and replenish their energy reserves.

Habitat: This cetacean alternates its annual life cycle between two distinct marine environments. During the mating and calving months, it inhabits shallow, warm coastal waters, showing a clear preference for sheltered bays, semi-enclosed gulfs, and shallow inlets where wave action is low and environmental conditions protect mothers and newborn calves from marine predators. Conversely, during the summer feeding season, it moves to pelagic, open-ocean habitats in the Southern Ocean, often associating with current convergence zones, thermal fronts, and ice-shelf edges where massive nutrient upwelling occurs.

Feeding: It is categorized as a continuous filter feeder that employs a passive skimming technique. To feed, it swims slowly at the surface or at mid-water depths with its mouth agape, allowing water to flow through its long, hair-like baleen plates, which act as a highly efficient sieve to retain prey. Its primary diet consists of small zooplankton organisms, showing a strong preference for copepods (especially of the genus Calanus) and, to a lesser extent, Antarctic krill (Euphausia superba) and the larval stages of various decapod crustaceans, consuming several tons of these tiny organisms daily during its stay in the deep southern feeding grounds.

Behavior: Despite its colossal dimensions, it is highly active and curious at the water surface. It is common to observe a wide range of aerial displays, including spectacular breaches, lobtailing (slapping the fluke against the water surface), and repetitive flipper slapping. A unique and distinctive behavior of this species is sailing, where the whale positions its tail fluke vertically out of the water and keeps it exposed to the wind for several minutes, seemingly using it as a sail for play or thermoregulation. It is a slow-swimming species, with average cruising speeds rarely exceeding 9 kilometers per hour, a characteristic that historically made it an easy target for whalers. Its vocalizations consist of low-frequency sounds described as moans, pulses, and groans, which are essential for maintaining social cohesion and facilitating courtship.

Reproduction: The reproductive biology of this species involves a polygynandrous mating system, where multiple males compete non-violently through sperm competition for a single receptive female, forming active surface mating groups. Females have a 12-month gestation period, giving birth to a single calf that measures approximately 4.5 to 6 meters in length at birth. The reproductive rate is slow, with a typical calving interval of three years. The mother provides intensive parental care within the sheltered calving grounds, nursing the calf with extremely fat-rich milk for about a year, during which the calf doubles or triples its size before weaning and starting its first migration.

Conservation status: It is currently classified as Least Concern (LC) on the IUCN Red List, reflecting significant population recovery following the international ban on commercial whaling. However, some localized subpopulations remain threatened or critically endangered. Today, the main anthropogenic threats hindering full recovery include ship strikes in busy shipping lanes, entanglement in fishing gear from industrial fisheries, ocean noise pollution from seismic surveys, and climate change, which alters the distribution and abundance of krill and copepods in their summer feeding grounds.