Spade-Toothed Whale

## Description

The spade-toothed whale (Mesoplodon traversii ) is a very little-known species, the rarest species of beaked whale. It was first named from a partial jaw found on Pitt Island, New Zealand, in 1872; reported and illustrated in 1873 by James Hector (referring it to M. layardii ), and described as a new species the next year by John Edward Gray, who named it in honor of Henry Hammersley Travers, the collector. This was eventually lumped with the strap-toothed whale, starting as early as an 1878 article by Hector, who never considered the specimen to be specifically distinct. A calvaria found in the 1950s at White Island, also New Zealand, initially remained undescribed, but was later believed to be from a ginkgo-toothed beaked whale.

In 1993, a damaged calvaria was found washed up on Robinson Crusoe Island, Chile, and was described as a new species, Mesoplodon bahamondi or Bahamonde's beaked whale.

In December 2010, two specimens, a cow and calf, were found stranded on Opape Beach, Bay of Plenty, New Zealand. They were originally thought to be Gray's beaked whale, but later genetic analysis revealed that they represented the first complete specimens of the spade-toothed whale. Following this find, a report describing the spade-toothed whale and an analysis of their DNA later appeared in the 6 November 2012 issue of the journal Current Biology.

The results of DNA sequence and morphological comparisons have shown all three finds came from the same species, which is therefore properly known as M. traversii. The external appearance was only described in 2012, and it is likely to be the most poorly known large mammalian species of modern times.

Because of where these specimens were initially located at, it is assumed that the remaining population of *M. traversii* lives solely in the South Pacific.

## Appearance

This cetacean is probably the least known whale on the planet. Spade-toothed beaked whale is currently an insufficiently explored species, since the animal has never been seen in the wild. All available information about this species comes from skeletal remains, consisting of two skulls and one jawbone. These remains suggest skull morphology, which is very similar to that of the strap-toothed beaked whale. The color of their skin is unknown. This animal is thought to be a medium sized beaked whale of 5.0 - 5.5 m (16 - 18 ft) in length. Males are likely to have 2 large tusks, which emerge half-way along their bottom jaw, curling up over the beak.

## Distribution

Only three specimens of this species have ever been found by humans. The animals have been seen in New Zealand and Chile, suggesting that they live in the southern hemisphere. It is possible that their range is restricted to the South Pacific.

## Behavior

Due to lack of observations in the wild, there is no information on habits of Spade-toothed whales.

## Diet

Spade-toothed whales possibly have the same diet as other whales of their family, which consume fish, squid and different species of crustaceans.

## Reproduction

Currently, there is no information on reproductive behavior of this species due to lack of observations in the wild.

## Population

### Population threats

As these animals have never been seen in the wild, a possible threat of poaching or hunting may be excluded. However, they may suffer from loud human-made sounds such as those produced by navy sonar and seismic exploration. Living in temperate waters, the Spade-toothed whales may be threatened by climate change, causing ocean warming, which in turn leads to reduction and modification of their natural range.

### Population number

According to the IUCN Red List, the total population size of the Spade-toothed whales is unknown for today. Currently, this species is classified as Data Deficient (DD) on the IUCN Red List.

## Fun Facts for Kids

Spade-toothed whales are so called due to a part of their tooth, emerging from the gum and reminding the tip of a flensing spade, which was commonly used by whalers in the 19th century.

Eyes of these cetaceans are quite small for their body size since they primarily perceive the environment through their sense of hearing.

When swimming, whales move their tails up and down, while flippers allow them to make turns.

When on their migratory route, whales don't eat: they only swim and take short rests, until they get to their destination point. During migration, they occasionally swim close to the shoreline, and observers can see them breaching (this is when a whale jumps out of the water) and blowing.

Moby Dick, written by Herman Melville, is the most famous story about whales. The book features a whaler, who hunts for an elusive white sperm whale. As a matter of fact, a very rare albino sperm whale is sometimes called 'Moby Dick' just like the title character of the eponymous book.