Odontocetes

Life in the ocean provides unique navigational, foraging, and socializing challenges for marine mammals. As a result, they have adapted complex communication systems. The complex acoustic signals span from tonal (continuous sounds likely consisting of frequency modulation - meaning that the energy over the course of the signal changes frequency) to pulsed (rapid burst) sounds. Tonal sounds are strongly linked to socializing events, while pulsed sounds are typically linked to navigation and foraging. However, there are exceptions in odontocete call types such as sperm whale codas.

Foraging calls
While all members of the cetacean family exhibit complex communication, odontocetes have evolved a unique tool that baleen whales do not possess; echolocation. Odontocetes produce echolocation clicks. They have air sacs beneath their blowhole that they release through phonic “lips” (also known as “monkey lips”), which then is focused through their melon - consisting of fatty tissue with similar densities to seawater - that allow the pulsed signal to be focused and transmit better in water. The sound waves from these signals reflect off objects, providing valuable information about environmental topography, prey, etc. Foraging odontocetes also produce ‘buzz’ sounds, a series of rapid echolocation clicks. Different odontocete groups produce clicks at different ranges, known as the interclick interval (see below), which can be used to help identify the sound source.

Social calls
Many odontocetes exhibit socializing calls, including whistles and burst pulses. Whistles are one of the most studied odontocete vocalizations, and are frequency modulated, narrow-band calls. Many dolphin species adopt a ‘signature whistle’ in their first few years of life, which is equivalent to that animal’s “name”. Burst pulses are another social call-type. These are high-frequency pulsed calls, which are emitted quickly and typically broadband. However, they can be difficult to describe as they are incredibly variable. Depending on the species, burst pulses can be described as creaks, squacks, barks, and pops. It is important to note, not all species whistle/and or produce burst pulses.

See our odontocete study species below for more information. Our species list is organized by sperm whale, dolphins, beaked whales, and narrow band high-frequency (NBHF) species (Porpoise, Kogiidae). Each section includes call types, spectra imagery, and wigner plots if applicable.

Sperm whale

Scientific name: Physeter macrocephalus
Makara species code: SPWH

Sperm whales produce echolocation clicks and foraging buzzes (also known as creaks) similar to other odontocete groups. Sperm whale buzzes are emitted during foraging, typically right before prey capture. Sperm whales do not produce whistles, however their social call types include codas, slow clicks (also known as clang), trumpets and social buzzes.

Codas are a patterned sequence of broadband clicks, and are thought to be used for social communication and group cohesion. Female and juvenile sperm whales live in social units which will have a vocal dialect made up of more than 20 different coda types. Slow clicks are typically produced by males, and are thought to be used for long-distance communication. Below is a list of vocalizations monitored by the PAB.

Call Types			Makara call-type code
Foraging
Echolocation click			SPUSC
Creak			SPCREAK
Foraging Mix			SPFORG (includes foraging buzzes)
Social
Coda			SPCODA
Slow click/clangs			SPSLCC
Social buzz			SPSOCBZ
Trumpet			SPTRUMPET
Squeal			SPSQUEAL
Social mix			SPMIX

Spectrograms showing the Acoustic Events associated with trumpet emissions using Raven 2.0 (FFT and Hanning window size 1024 (A) and 512 (**B, C, D**), 50% overlap). A Regular, **B, C, D** multi-pattern arrangements (Pace et al. 2021)

Dolphins

Dolphin species produce various clicks and whistles which are complex, variable, and often overlapping. Clicks are often associated with foraging, whereas tonal whistles and burst pulses are associated with social communication.

Call Types			Makara call-type code
Foraging
Echolocation clicks			ODCLICK
Social
Whistles			ODWHIS
Burst pulse			ODBP
Mixed calls			ODMIX

Note

PAB typically does not differentiate individual dolphin species for soundtrap data analysis, but will identify species for towed array surveys

Atlantic Spotted Dolphin Whistles

Dolphin clicks

Through our concurrent visual and acoustic studies, we are starting to be able to group our delphinid study species by general click characteristics: Broadband, clicks with a 30-50 kHz peak, and low-frequency high-amplitude (blackfish). Broadband species produce clicks with a wide frequency range, and consists of Bottlenose and Common dolphins.

The second delphinid group is characterized by clicks with an amplitude peak within the 30 - 50 kHz frequency range. See figure for 30-50 kHz peak click spectra and species composition.

The final delphinid group is characterized by low frequency, high amplitude clicks. These are our blackfish species, which are also our largest delphinid species - false killer whales and pilot whales. Blackfish, along with belugas and narwhals, are unique in their ability to biphonate- produce multiple frequency sounds simultaneously. This occurs in their pulsed calls (see below).

Spectrographic example of a pilot whale pulsed call. Calls may consist of two components, an upper frequency component (UFC) that is a narrow-band tone, and a lower frequency component (LFC) that is a broadband pulse. The pulse repetition rate (PRR) is reflected by the sideband interval (SBI). Elements are distinguished by abrupt shifts in the PRR (Nemiroff & Whitehead 2009).

Broadband & 30 - 50 kHz species

Atlantic spotted dolphin

Scientific name: Stenella frontalis
Makara species code: WSDO

Atlantic White-sided dolphin

Scientific name: Lagenorhynchus acutus
Makara species code: WSDO

Bottlenose dolphin

Scientific name: Turiops truncatus
Makara species code: BODO

Common dolphin

Scientific name: Delphinus spp.
Makara species code: SADO

Note

Long-beaked and Short-beaked common dolphins cannot be differentiated acoustically

Risso’s dolphin

Scientific name: Grampus griseus
Makara species code: GRAM

Rough-toothed dolphin

Scientific name: Steno bredanesis
Makara species code: RTDO

Striped dolphin

Scientific name: Stenella coeruleoalba
Makara species code: STDO

Spinner dolphin

Scientific name: Stenella longirostris
Makara species code: SNDO

Blackfish species

False killer whale

Scientific name: Pseudorca crassidens
Makara species code: FKWH

Pilot whale sp.

Scientific name: Globicephala spp.
Makara species code: SFPW

Note

Long-finned and Short-finned pilot whales cannot be differentiated acoustically

Beaked Whales

Beaked whales produce two types of clicks - Frequency modulated upsweeps and surface clicks (not frequency modulated, also refered to as impulsive clicks). Frequency modulated upsweeps refers to echolocation clicks produced during foraging events. Similar to sperm whales, beaked whales produce buzzes(rapid echolocation clicks) right before prey capture. Some beaked whale species emit impulsive clicks, which are considered social communication. These are predominantly larger beaked whale species (ex. Northern bottlenose whale and Baird’s beaked whales). Some species may produce whistles as well, however they are uncommon and not well documented.

Call Types			Makara call-type code
Foraging
Frequency modulated upsweeps			BWFMUP
Pulse call			(Specie abbrv.)BWPULSE
Social
Impulsive click			(Specie abbrv.)BWCLICK
Whistle			(Specie abbrv.)BWWHIS

Note

(Specie abbrv.) Is the first two letters of the species’ common name. For example, a Sowerby’s beaked whale pulse call would be SOBWWHIS.

Beaked whale clicks

Each beaked whale species in the Northeast Region have slightly different click structures, as shown below in a combined click power spectra plot. Note, the power spectra are average values for each species, and individual clicks for each species may differ slightly. Under each beaked whale species heading is a an exemplar click’s Wigner plot, which is the primary tool for determining beaked whale species from a click. Wigner plots were made in Pamguard and are high resolution spectrograms that show the details of the click’s spectral structure. For more information on this software, see our software page.

Sowerby’s beaked whale

Scientific name: Mesoplodon bidens
Makara species code: SOBW

Blainville’s beaked whale

Scientific name: Mesoplodon densirostris
Makara species code: BLBW

Gervais’ beaked whale

Scientific name: Mesoplodon europaeus
Makara species code: GEBW

True’s beaked whale

Scientific name: Mesoplodon mirus
Makara species code: TRBW

Goose beaked whale

Scientific name: Ziphius cavirostris
Makara species code: CUBW

Gulf of Mexico’s Beaked whale (BWG, unknown)

Scientific name: Ziphiidae sp.
Makara species code: BWG

Narrow band high-frequency (NBHF)

Narrow high-band frequency species include porpoises and Kogiidae species (Pygmy and Dwarf sperm whales). Both groups produce indifferentiable clicks. Species are thus identified by recording location - nearshore narrow high-band frequency clicks are denoted as porpoise clicks, offshore as Kogiidae clicks (map right). Porpoises also produce both social and foraging buzzes, indicating an echolocation event.

Call Types			Makara call-type code
All Kogiidae species
Narrow band high frequency clicks			NBHF
Harbor Porpoise only
Buzz			POBZ (both foraging and social)

Kogia click spectra: PSD of the energy distribution within Kogia clicks

Note

For Kogia 3: the peak ~117 kHz is an artifact of the high pass filter applied to the data, thus Kogia 3 spectra = Kogia 2 spectra

Narrow Band High Frequency click (*Malinka et al. 2021*)

Harbor porpoise

Scientific name: Phocoena phocoena
Makara species code: HAPO

Pygmy sperm whale

Scientific name: Kogia breviceps
Makara species code: PSWH

Dwarf sperm whale

Scientific name: Kogia sima
Makara species code: DSWH

Sources

Annamaria Izzi DeAngelis, Joy E. Stanistreet, Simone Baumann-Pickering, Danielle M. Cholewiak; A description of echolocation clicks recorded in the presence of True’s beaked whale (Mesoplodon mirus). J. Acoust. Soc. Am. 1 November 2018; 144 (5): 2691–2700. https://doi.org/10.1121/1.5067379

Chloe E. Malinka, Pernille Tønnesen, Charlotte A. Dunn, Diane E. Claridge, Tess Gridley, Simon H. Elwen, Peter Teglberg Madsen; Echolocation click parameters and biosonar behaviour of the dwarf sperm whale (Kogia sima). J Exp Biol 15 March 2021; 224 (6): jeb240689. doi: https://doi.org/10.1242/jeb.240689

Malinka CE, Tønnesen P, Dunn CA, Claridge DE, Gridley T, Elwen SH, Teglberg Madsen P. Echolocation click parameters and biosonar behaviour of the dwarf sperm whale (Kogia sima). J Exp Biol. 2021 Mar 26;224(Pt 6):jeb240689. doi: 10.1242/jeb.240689

Nemiroff L, Whitehead H. Structural characteristics of pulsed calls of long-finned pilot whales Globicephala melas. Bioacoustics. 2009;19:67–92. doi: 10.1080/09524622.2009.9753615.

Pace, D.S., Lanfredi, C., Airoldi, S. et al. Trumpet sounds emitted by male sperm whales in the Mediterranean Sea. Sci Rep 11, 5867 (2021). https://doi.org/10.1038/s41598-021-84126-8