True's Beaked Whale
About the Species
True’s beaked whales are little known members of the beaked whale family, Ziphiidae. They can be found in deep, warm, temperate waters of the North Atlantic Ocean as well as at least two other areas in the Southern Hemisphere. They receive their common name from Frederick W. True, a curator at the Smithsonian Institution, who described the species from an animal that stranded on a beach in North Carolina.
There is little information on the abundance of True’s beaked whales worldwide. The beaked whale family is cryptic and skittish and distinguishing between species in the field can be challenging.
Like all marine mammals, True’s beaked whales are protected under the Marine Mammal Protection Act and face threats from human-caused ocean noise. True’s beaked whales are considered “data deficient” by the International Union for Conservation of Nature’s list of threatened species, meaning that there is not enough information to assess their population status.
NOAA Fisheries estimates population size for True’s beaked whales in its stock assessment reports. A stock is a group of animals that occupy the same area and interbreed. Due to the rarity of sightings at sea, there is little information on the abundance of this species worldwide. Thus, data are insufficient to estimate population size or trends.
True's beaked whales have a relatively small- to medium-sized body with a moderately short beak, as well as a rounded, sloping forehead (known as a melon). They have a small, wide-based, slightly hooked dorsal fin located far down their back. Their coloration varies from gray to brown on the dorsal side with a paler ventral side. In the field, they are distinguished from Gervais’ beaked whales (which are similar in appearance) by the pale coloration across their melon and lack of a dark, defined dorsal stripe.
True’s beaked whales in the Southern Hemisphere have more white coloration on their back, tailstock, and underside than those in the Northern Hemisphere. Mature males may have linear scarring covering their body from battling other males for access to females during mating. This species is difficult to observe and identify at sea due to a low profile at the surface and a small, inconspicuous blow. Few have been seen alive at sea.
As adults, True's beaked whales can reach lengths of 15.5 to 17.5 feet and weigh from 2,200 to more than 3,000 pounds. Females may be slightly larger than males. Mature males can be distinguished from females and juveniles by a pair of teeth visible on the tip of their lower jaw. The mouthline is typically straight or slightly curved.
Behavior and Diet
When observed, True's beaked whales are often alone or in small, closely associated groups averaging five to six animals. While diving, they use suction to feed on small fish and cephalopods (e.g., squid) in deep waters. This species has been known to breach and occasionally display surface active behaviors.
Even when dead, many species of beaked whales (especially those in the genus Mesoplodon) are difficult to distinguish from one another because they lack easily discernible or apparent physical characteristics. At sea, they are also challenging to observe and identify to the species level because of their cryptic, skittish behavior, low profile, and small, inconspicuous blow at the water’s surface. Therefore, much of the available characterization for beaked whales is to the genus level only.
Where They Live
True's beaked whales prefer deep warm temperate waters of the North Atlantic Ocean as well as at least two other areas in the Southern Hemisphere (e.g., Indian Ocean). Their range, which is mostly known from strandings, includes areas off of Nova Scotia, Canada, Bay of Biscay, Ireland, Europe, the Azores, the Canary Islands, Bermuda, Florida, and the Bahamas in the Atlantic, as well as off the coasts of Brazil, Madagascar, South Africa, New Zealand, and southern Australia. It is unknown whether this species migrates or exhibits seasonal shifts in habitat use.
Lifespan & Reproduction
The lifespan of this species is unknown, and very little is known about their reproduction. Females generally give birth to a single calf that is about 6.5 to 8 feet long and weighs about 300 pounds.
Deep-diving cetaceans like True’s beaked whales use sound to feed, communicate, and navigate in the ocean. This species may be sensitive to underwater sounds and human-made noise. Sound pollution threatens them by interrupting their normal behavior and driving them away from areas important to their survival, such as breeding and feeding waters.
In the Spotlight
Like all marine mammals, the True’s beaked whale is protected under the Marine Mammal Protection Act. NOAA Fisheries is working to conserve this species to ensure populations remain stable.
Overseeing Marine Mammal Health and Stranding Response
We work with volunteer networks in all coastal states to respond to marine mammal strandings including all whales. When stranded animals are found alive, NOAA Fisheries and our partners assess the animal’s health and determine the best course of action. When stranded animals are found dead, our scientists work to understand and investigate the cause of death. Although the cause often remains unknown, scientists can sometimes attribute strandings to disease, harmful algal blooms, vessel strikes, fishing gear entanglements, pollution exposure, and underwater noise. Some strandings can serve as indicators of ocean health, giving insight into larger environmental issues that may also have implications for human health and welfare.
Marine Mammal Unusual Mortality Events
True’s beaked whales have never been part of a declared unusual mortality event. Under the Marine Mammal Protection Act, an unusual mortality event is defined as "a stranding that is unexpected; involves a significant die-off of any marine mammal population; and demands immediate response." To understand the health of marine mammal populations, scientists study unusual mortality events.
Addressing Ocean Noise
NOAA Fisheries is investigating all aspects of acoustic communication and hearing in marine animals, as well as the effects of sound on beaked whale behavior and hearing. For example, the use of at least some types of shipboard echosounders decreases the acoustic detection rates of multiple species of beaked whales, indicating that they change their behavior when they hear these echosounders. In 2018, we revised technical guidance for assessing the effects of human-made sound on marine mammal hearing.
Like all marine mammals, True’s beaked whales are protected under the MMPA.
Key Actions and Documents
NOAA Fisheries conducts a variety of research on the biology, behavior, and ecology of beaked whales. The results of this research are used to inform management decisions and enhance protection efforts for this and other beaked whale species.
Determining the population size of the True’s beaked whales helps resource managers measure the success of NOAA Fisheries’ conservation measures. Our scientists collect and present these data in annual stock assessment reports.
NOAA Fisheries conducts research cruises to collect information on beaked whale stocks, including habitat preferences and feeding ecology. For example, the Northeast Fisheries Science Center conducted a shipboard survey in which they identified new habitat for True’s beaked whales off the U.S. east coast. Cruises also help us estimate the abundance of beaked whales. Information from this research can be used in management actions to protect these animals.
Our research is also focused on acoustics—using underwater sound to learn more about the species. We study the basic acoustic behavior of cetaceans and fish, mapping the acoustic environment and finding better ways to find cetaceans using passive acoustic technologies. For example, we tow arrays of hydrophones behind ships to acoustically detect and locate True’s beaked whales during surveys. We also use archival bottom-mounted recorders to monitor long-term occurrence of the species at specific recording sites. Our acoustic research also assesses the degree to which human-caused activities are changing the underwater soundscape, how these changes may potentially impact marine animals, and what measures can be taken to mitigate these potential impacts.