Rice's whale facts for kids

Quick facts for kids Rice's whale
Rice's whale in the Gulf of Mexico
Size compared to an average human
Conservation status
Critically Endangered (IUCN 3.1)
Scientific classification
Genus:	Balaenoptera
Species:	ricei
Core range as of June 2019
Synonyms
Balaenoptera edeni brydei Rice, 1998

Rice's whale (Balaenoptera ricei) is a species of baleen whale endemic to the north-eastern Gulf of Mexico. It was historically identified as a subspecies of the Bryde's whale and known as the Gulf of Mexico Bryde's whale. Its status as distinct from this species was first established in 2014 by two geneticists, who found mitochondrial and nuclear DNA evidence indicating the gulf population was a distinct lineage and possibly a new species most closely related to the Eden's whale. Additional genetic and anatomical evidence published in a 2021 follow-up study confirmed this status. The common name Rice's whale and specific epithet ricei honor the cetologist Dale W. Rice (1930–2017).

Description and behavior

Aerial photo of a Rice's whale

It is an intermediate-sized rorqual, reaching a length of up to 12.65 meters (41.5 ft). This corresponds to a weight of around 13.87 metric tons (13.65 long tons; 15.29 short tons) according to a length-weight function developed by Ohsumi (1980). Rice's whale are long and slender, with 44 to 54 ventral grooves that extend beyond the umbilicus. They have 230 to 288 pairs of baleen plates that are up to 44.2 cm (17.2 inches) long. They have short, narrow flippers up to 1.65 m (5.4 ft) long. Their dorsal fin is upright and falcate and up to 37.8 cm (14.9 inches) tall. Their flukes are smooth-edged and up to 3.16 m (10.4 ft) wide. Little is known about the ecology of Rice's whales, and hypotheses about their diet and behavior are largely inferred from those of Bryde's whales. Rice's whales are typically sighted alone or in pairs, but they occasionally form large loose groups that are believed to be associated with feeding. Rice's whales make daytime foraging dives as deep as 271 m (889 ft), while at night they typically stay within 15 m (49 ft) of the surface, occasionally making deeper dives of 150 m (490 ft).

Distribution and habitat

Although some scientists believe that it may have historically inhabited the entire Gulf of Mexico, the species is now consistently sighted only within a small stretch of the gulf's north-eastern section characterized by a continental shelf between 100 meters (330 ft) to 400 meters (1,300 ft) deep, where they remain year-round. There is a possibility that some populations may exist in Cuban and Mexican waters (hence the current population estimate is only "fewer than 100" even though only 33–44 individuals are known from US waters), but currently the only population known is in US waters. They are the only resident baleen whales known from the Gulf of Mexico, with other species in the area being migratory.

Phylogeny

The following cladogram is modified from a phylogenetic analysis by Rosel et al. (2021) based on genetic data.

Discovery

This species had been documented by whalers in the Gulf of Mexico since 1790, and its now-small distribution was first noticed in the 1990s. In 2014, a genetic study found Rice's whale to likely represent a distinct species or subspecies of whale. The description of the species was hampered by the lack of a good study specimen until early 2018, when a beached individual was found in Everglades National Park in Florida and was later transported to the Smithsonian. This provided a specimen of the species without having to kill or harm any of the already-endangered population and allowed for taxonomic studies to confirm its distinctiveness.

Conservation status

Scientists performing a necropsy on a Rice's whale that washed up at Everglades National Park

Prior to its formal description as a distinct species, Rice's whale was separately assessed by the IUCN Red List as "Gulf of Mexico whale", and is listed as critically endangered. It is also listed as an endangered species by the United States under the Endangered Species Act. Its current population is estimated as below 100, with as few as 17 being of mature age, making it one of the most endangered cetaceans. Although some reports of whaling of "finback whales" in the Gulf of Mexico during the 18th and 19th century are likely to include Rice's whales, there are no recorded counts of kills for this species, and an assessment by the NOAA determined that hunting was unlikely to be a major contributing factor for the species' small population. The 2010 Deepwater Horizon oil spill inflicted serious harm to the remaining Rice's whale population; a study found that 48% of the species was exposed to the oil, of which 18% suffered adverse health effects, including reproductive failure in 22% of females. This has led to an estimated 22% decrease in the Rice's whale population. Collisions with vessels and increased underwater noise events in the Rice's whales' habitat are other primary anthropogenic threats.

Images for kids

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  Variations in dorsal fins and backs

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  Closeup of USNM 594665's mouth, showing the blackening of baleen in the upper posterior positions

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  Diagram of a diel vertical diving pattern

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  Lanternfish (shown) and hatchetfish are possible prey of the Rice's whale.

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  A Rice's whale with a deformed back caused by a ship strike

See also

In Spanish: Rorcual de Rice para niños