---
title: "What the sources say about the Bottlenose Dolphin | AnimalTracks.wiki"
description: "39 claims from the Bottlenose Dolphin profile, each beside the words of the source that backs it."
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---

# What the sources say about the Bottlenose Dolphin (*Tursiops truncatus*)

> 39 claims from the Bottlenose Dolphin profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Bottlenose Dolphin](https://animaltracks.wiki/animals/bottlenose-dolphin/)

## Common Bottlenose Dolphin. NOAA Fisheries.

https://www.fisheries.noaa.gov/species/common-bottlenose-dolphin

| The page says | The source says |
| :--- | :--- |
| 6 to 13 feet long and weigh 300 to 1,400 pounds | Weight 300 to 1,400 pounds Length 6 to 13 feet |
| NOAA Fisheries says they can live at least 40 years, with some females outliving males at 60 years or more. | Bottlenose dolphins can live at least 40 years, with some females outliving males at 60 years or more. |
| Females as old as 45 have given birth | Females as old as 45 have given birth. |
| NOAA lists bottlenose dolphins as likely to go through menopause, like humans, killer whales, belugas and narwhals | species known to undergo menopause include humans, short-finned pilot whales, narwhals, beluga whales, killer whales, false killer whales, and likely, bottlenose dolphins |
| They feed on a variety of prey, such as fish, squid, and crustaceans like crabs and shrimp. | feed on a variety of prey, such as fish, squid, and crustaceans (e.g., crabs and shrimp) |
| They may work together to herd fish into groups and take turns charging through the school, or trap schools of fish against sandbars and seawalls for an easy meal. | searching for food individually or cooperatively. For example, they work together to herd fish into groups and then take turns charging through the school of fish to feed. Bottlenose dolphins may also trap schools of fish against sand bars and seawalls for an easy meal. |
| They do not chew: a dolphin grips a fish in its teeth and swallows it whole, head first, so the spines do not catch in its throat | Instead of using their teeth to chew, bottlenose dolphins grip fish with their teeth, then swallow the fish whole—head first—so the spines of the fish don't catch in their throats. |
| To find prey, they use passive listening, high-frequency echolocation, or both. | They use passive listening and/or high frequency echolocation to locate prey. |
| Temperate and tropical waters worldwide, from harbors, bays and estuaries to far offshore in the open ocean | Bottlenose dolphins are found in temperate and tropical waters around the world. They inhabit a wide variety of habitats, including harbors, bays, gulfs, and estuaries, as well as nearshore coastal waters, deeper waters over the continental shelf, and even far offshore in the open ocean. |
| A variety of prey such as fish, squid, crabs and shrimp, with fish sometimes herded into groups or trapped against sandbars and seawalls | feed on a variety of prey, such as fish, squid, and crustaceans (e.g., crabs and shrimp). ... they work together to herd fish into groups ... Bottlenose dolphins may also trap schools of fish against sand bars and seawalls for an easy meal. |
| Bottlenose dolphins are found in temperate and tropical waters around the world, from harbors, bays and estuaries to far offshore in the open ocean | Bottlenose dolphins are found in temperate and tropical waters around the world. They inhabit a wide variety of habitats, including harbors, bays, gulfs, and estuaries, as well as nearshore coastal waters, deeper waters over the continental shelf, and even far offshore in the open ocean. |

## Tursiops truncatus (bottlenosed dolphin). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Tursiops_truncatus/

| The page says | The source says |
| :--- | :--- |
| Each dolphin is believed to keep its own signature whistle for life | Each dolphin is believed to possess its own signature whistle and, once it is developed, it is retained for the duration of the dolphin's life. (note: tagline, first half) |
| adult males typically grow bigger than adult females | Adult males are usually between 244 and 381 cm long, and weigh about 500 kg. Adult females are typically between 228 and 366 cm, and weigh about 250 kg. ... Sexual Dimorphism male larger |
| Larger sharks, such as bull, tiger, and dusky sharks, are their most common predators, and these sharks prey on smaller dolphins, calves and females more than larger dolphins | The most common predators of bottlenosed dolphins are larger sharks, such as bull (Carcharhinus leucas), tiger (Galeocerdo cuvier), and dusky sharks (Carcharhinus obscurus). These sharks prey on smaller dolphins, calves and female dolphins more than larger dolphins. |
| It is not uncommon to see dolphins bearing shark bites, proof they survived an attack. | It is not uncommon to observe dolphins with shark bites, demonstrating their survival of an attack. |
| Blubber may give some protection against predators. | Blubber may provide some protection against predators. |
| Each dolphin is believed to have its own signature whistle and to keep it for life, and calves can develop one as young as one month old | Each dolphin is believed to possess its own signature whistle and, once it is developed, it is retained for the duration of the dolphin's life. ... Signature whistles develop in calves as young as one month |
| Half its brain rests at a time. | It turns out that they rest one side of their brains while decreasing their activity level. (note: the blockquote's bold lead-in) |
| A dolphin has to surface to breathe, and it sleeps by resting one side of its brain while lowering its activity level. | One may wonder how dolphins, as marine animals that must surface to breathe every few minutes, sleep. It turns out that they rest one side of their brains while decreasing their activity level. |
| That lets it rest yet stay conscious enough to breathe and carry on basic survival behaviors. | This allows them rest and yet remain 'conscious' to breathe and carry on basic survival behaviors. |
| Echolocation calls pass through the melon, a fatty lens for sound that focuses the outgoing calls, while a fatty pad in the lower jaw focuses sound to each ear. | Echolocation calls pass through the melon and intramandibular fat body, which contain acoustic lipids; these structures serve as acoustic lenses to focus sound. The intramandibular fat bodies focus sound to each ear, while the melon is used as a lens to focus outgoing sound. |
| Dolphins use echolocation to navigate and to detect the shape of the seafloor, prey and the presence of predators. | Bottlenosed dolphins also navigate with echolocation, used to detect bottom topography, prey, and the presence of predators. |
| A bottlenose dolphin rests one half of its brain at a time while lowering its activity level. That keeps it conscious enough to breathe and carry on other basic survival behavior even while it rests. | It turns out that they rest one side of their brains while decreasing their activity level. This allows them rest and yet remain 'conscious' to breathe and carry on basic survival behaviors. |
| The melon is a fatty lens for sound that focuses the outgoing calls a dolphin makes for echolocation, while a fatty pad in its lower jaw focuses sound to each ear. | Echolocation calls pass through the melon and intramandibular fat body, which contain acoustic lipids; these structures serve as acoustic lenses to focus sound. The intramandibular fat bodies focus sound to each ear, while the melon is used as a lens to focus outgoing sound. |
| Dolphins use echolocation to detect prey, the shape of the seafloor, and predators. | Bottlenosed dolphins also navigate with echolocation, used to detect bottom topography, prey, and the presence of predators. |

## Wells, Natoli & Braulik (2019). Tursiops truncatus. The IUCN Red List of Threatened Species 2019: e.T22563A156932432.

https://doi.org/10.2305/iucn.uk.2019-1.rlts.t22563a156932432.en

| The page says | The source says |
| :--- | :--- |
| Least Concern | IUCN Red List category: Least Concern (LC). |

## Janik & Slater (1998). Context-specific use suggests that bottlenose dolphin signature whistles are cohesion calls. Animal Behaviour.

https://doi.org/10.1006/anbe.1998.0881

| The page says | The source says |
| :--- | :--- |
| A 1998 study of four captive dolphins found that each one mainly made its own signature whistle when it was apart from the group, strong support for the idea that the whistle keeps the group together | we examined whistle type usage in a group of four captive bottlenose dolphins in two contexts. ... Each dolphin primarily produced one stereotyped signature whistle when it was separated from the group. ... The results strongly support the hypothesis that signature whistles are used to maintain group cohesion. (note: the year 1998 is the reference's publication year, not text inside the abstract) |
| Studies of captive bottlenose dolphins have shown that each one produces its own individually specific signature whistle. | Studies on captive bottlenose dolphins, Tursiops truncatus, have shown that each individual produces a stereotyped, individually specific signature whistle |
| A 1998 study of four captive dolphins found that each mainly made its own signature whistle when it was apart from the group, and almost only other whistles when all four shared a pool. | a group of four captive bottlenose dolphins ... Each dolphin primarily produced one stereotyped signature whistle when it was separated from the group. ... If all animals swam in the same pool almost only nonsignature whistles were used. (note: the year 1998 is the reference's publication year, not text inside the abstract) |
| That strongly supports the idea that signature whistles help keep a group together. | The results strongly support the hypothesis that signature whistles are used to maintain group cohesion. |

## Janik, Sayigh & Wells (2006). Signature whistle shape conveys identity information to bottlenose dolphins. Proceedings of the National Academy of Sciences.

https://doi.org/10.1073/pnas.0509918103

| The page says | The source says |
| :--- | :--- |
| In a 2006 study, dolphins could still tell whose signature whistle they were hearing after researchers removed all its voice features. | This study demonstrates that bottlenose dolphins extract identity information from signature whistles even after all voice features have been removed from the signal. (note: the year 2006 is the reference's publication year, not text inside the abstract) |
| At the time, dolphins were the only animals other than humans shown to pass on identity information independent of the caller's voice. | Thus, dolphins are the only animals other than humans that have been shown to transmit identity information independent of the caller's voice or location. (note: dated to the 2006 paper because it states a record, and the source is from 2006) |
| In a 2006 study, dolphins could still tell whose signature whistle they were hearing after researchers removed all its voice features. | bottlenose dolphins extract identity information from signature whistles even after all voice features have been removed from the signal (note: FAQ 3; the year 2006 is the reference's publication year) |
| At the time, dolphins were the only animals other than humans shown to pass on identity information independent of the caller's voice. | dolphins are the only animals other than humans that have been shown to transmit identity information independent of the caller's voice or location (note: FAQ 3; dated to the 2006 paper because it states a record) |
| A signature whistle other dolphins can recognize even with its voice features removed, plus echolocation focused through a fatty lens for sound to find prey and read the seafloor. | bottlenose dolphins extract identity information from signature whistles even after all voice features have been removed from the signal (note: superpower; the melon-as-lens and prey and seafloor detection in the second half are covered by the adw-tursiops-truncatus claims on the body and FAQ 4) |

## Janik (2000). Whistle Matching in Wild Bottlenose Dolphins (Tursiops truncatus). Science.

https://doi.org/10.1126/science.289.5483.1355

| The page says | The source says |
| :--- | :--- |
| Wild dolphins also answer another dolphin's whistle by making the same whistle type, over distances of up to 580 meters, a sign of animals addressing each other individually | wild, unrestrained bottlenose dolphins use their learned whistles in matching interactions, in which an individual responds to a whistle of a conspecific by emitting the same whistle type. Vocal matching occurred over distances of up to 580 meters and is indicative of animals addressing each other individually. |
| for an animal that answers another dolphin's whistle by making the same whistle type | an individual responds to a whistle of a conspecific by emitting the same whistle type (note: vibe.reason; the words before "for" describe the track, and the song is "Wannabe" by the Spice Girls (re-paired in #877)) |

## Plotnik, de Waal & Reiss (2006). Self-recognition in an Asian elephant. Proceedings of the National Academy of Sciences.

https://doi.org/10.1073/pnas.0608062103

| The page says | The source says |
| :--- | :--- |
| dolphins have passed the mirror test for self-recognition | After the recent discovery of MSR in dolphins (Tursiops truncatus) (note: tagline, second half) |
| Dolphins have also passed the mirror test for self-recognition, which had long seemed limited to humans and apes, and that discovery made elephants the next logical species to test | mirror self-recognition (MSR) has long seemed limited to humans and apes. ... After the recent discovery of MSR in dolphins (Tursiops truncatus), elephants thus were the next logical candidate species. |