[9] The small size of this species also causes confusion with other dolphins especially where the frontal head shape of the animals encountered remains unseen.

Furthermore, in calmer waters the small bow wave pushed in front of the face looks like a bottle from a distance.

In 1967, a single pygmy killer whale off of Costa Rica died after becoming entangled in a purse seine net.

Finally, in 1969, a pygmy killer whale was killed off the coast of St. Vincent and a group of individuals was recorded in the Indian Ocean.

This is similar to the range of other odontocetes such as the bottlenose dolphin but is slightly higher than false killer whales.

[11] The anatomy for auditory reception is similar to other odontocetes, with a hollow mandible and a mandibular fat body composed of a low density outer layer and a denser inner core.

The inner core comes into direct contact with the tympanoperiotic complex (functionally similar to the auditory bulla in other species - see Cetacea).

Hearing tests performed on two live individuals brought in for rehabilitation exhibited frequency response range and temporal resolution similar to that found in other echolocating dolphins.

[14] Appearances in bycatch suggest a year-round presence in the Indian Ocean near Sri Lanka and the Lesser Antilles.

[16] In May 2023, a sailor named Bryant Irawan, spotted a pod much further north off the coast of Portugal, which was confirmed by scientists at happywhale.com.

[17] They have been observed along the coast of South America and as far north as the Gulf of Mexico where they have been known to breed during the spring season.

On August 3, 2024, three pygmy killer whales were found stranded in the mangroves of Ao Kung, Phuket.

They represent as much as 4% of the cetacean bycatch in drift gill nets used by commercial fisheries in Sri Lanka.

[21] A pygmy killer whale found stranded on the coast of New Caledonia died from parasitic encephalitis caused by nematodes.