Melon-headed whales, also called blackfish or the electra dolphin, are small whales in the dolphin family with bulbous, curved crowns that give their heads a melon-shaped appearance. They’re social creatures and travel in groups by the hundreds, and they’re often mistaken for pygmy killer whales which bear similar features.
Derivation: Their scientific name is Peponocephalia electra, with the Greek word pepon translating to melon or gourd, kephale for head, and electra for the sea nymph in greek mythology.
Taxonomic ID: 180458
Classification
| Kingdom | Animalia |
| Class | Mammalia |
| Order | Cetacea |
| Suborder | Odontoceti (toothed whale) |
| Family | Delphinidae |
| Genus | Peponocephala |
| Species | electra |
Characteristics
Melon-headed whales are odontocetes, or toothed whales, with sleek and dark oil-colored bodies with a dark-grey or whitish underbelly and white markings along their non-beaked but slightly pointed snout. Their faces are subtly masked, with a cape around the dorsal area, which extends further than the dorsal cape on a pygmy killer whale. The dorsal fin is tall, with a pointed tip and broad base, and its long flippers come to a sharp point. They’re full-bodied, with a girthy torso.
Neonates are born at 1 meter (3.3 ft) and 15 kg (33 lbs) while adults can reach 2.3-2.7 meters (7.5-9 feet) and 200-275 kg (440-605 lbs). Males can be slightly larger than females.
They’re toothed whales, and they have 40-52 teeth on their upper and lower jaw. They travel in large groups of hundreds, with smaller groups breaking off into subsets of the dominant group. Melon-headed whales can be discerned from pygmy killer wales from the size of the pod.
Where do they Live?
Melon-headed whales are found in deep, warm tropical waters off the coast of Hawaii and the Gulf of Mexico, but pods have also been spotted in the Western Atlantic, though recent spottings may have been a case of mistaken identity, as it is not confirmed whether the spottings in the Atlantic region were actually pygmy whales. There have been confirmed sightings in the Indian Ocean. In general, they’re between 20 degrees north and 20 degrees south, with some outliers – one sighting even in Ireland.
How Many Melon-Headed Whales are Left?
It’s estimated that approximately 45,000 melon-headed whales roam the eastern tropical Pacific, 3,000 in the Gulf of Mexico, and nearly 3,000 in Hawaii. Other regions are unknown.
What do they Eat?
Mesopelagic squid, small fish, and shrimp. A group of melon-headed whales that were tracked in Hawaii traveled to cyclonic and anticyclonic eddies in the region to forage.
Are they Endangered?
The IUCN has labeled melon-headed whales as “least concern,” or not endangered.
Threats
Melon-headed whales are subject to a number of threats like hunters and fishing nets, but mass-stranding events, where whales strand themselves on the shore, occur occasionally, like the one in Madagascar in 2008. The event involved approximately 100 melon-headed whales and resulted in over 75 deaths due to dehydration and sun exposure.
An independent review by the Independent Scientific Review Panel (ISRP) concluded that a high-powered echosounder system (MBES) operated by a survey vessel directly before the mass stranding event was likely the primary trigger for the whales to enter the lagoon and strand themselves on the shoreline.
Loud sounds in the ocean remain a top threat to melon-headed whales, as well as pollution, fishing nets, and climate change.
Protection
Melon-headed whales are protected under the Marine Mammal Act.
Discovery
Melon-headed whales were first recorded in 1841 and named John Edward Gray in 1846, but later it was determined that it was separate enough to be given its own genus, dubbed the Peponocephala in 1966 by Nishiwaki and Norris.
