With a length of around 10 ft. long, the melon-headed whale is considered a mid-sized dolphin. This dolphin species prefers swimming in warm waters and can be found living throughout the tropical/subtropical oceans of the world.
Although their name refers to them as whales, they are actually part of the dolphin family and are closely related to the pygmy killer whale, which is also a dolphin. The melon-headed whale is known to congregate into large pods of 100 – 1000 dolphins frequently and may be seen swimming alongside other species of dolphins.
Physical Characteristics and Appearance
When fully grown, the melon-headed whale can reach lengths of nearly 10 ft. long and weigh over 450 lbs. These dolphins have an oval-shaped body that tapers towards the flukes, and the head resembles the shape of melon and is triangular in nature as it runs towards the mouth.
The dorsal fin is a little large, triangular, and tapered back in nature near the middle of the back. The flippers are also tapered back and somewhat sickle-shaped along with the dolphin’s sides. In terms of color, they have a gray-colored body from the neck to the flukes and a darker gray face, while the belly area may appear to be a light gray to white coloring.
Diet and Hunting Methods
These dolphins are known to consume several different fish and squid. They may also occasionally consume various crustaceans.
When it comes to hunting for food at night or in dark areas, these dolphins are equipped with echolocation. They can bounce sounds off of objects in the area to determine the location, size, density, speed, and direction of the objects surrounding them.
Their echolocation is so advanced that they can easily determine whether the objects in their environment are food, a predator, or an inanimate object. Given their large pod sizes, they are likely to hunt in groups and use echolocation to organize hunting parties.
Habitat and Migration
The melon-headed whale prefers living away from the coastline traveling throughout the world’s tropical and subtropical climates. They have been spotting in several different locations such as South Africa, Southern England, Hawaii, Ireland, and the Philippines, among other tropical/subtropical regions. These marine mammals aren’t known to perform long migration trips regarding migration.
Social Structure and Communication
The melon-headed whale communicates using various high-pitched clicks and whistles to socialize and share interests with other dolphins. As a species, these marine mammals are a very social group known to travel in large pods of 100 – 1000 dolphins commonly.
During certain aggregations, pods may grow to include several thousand dolphins. When traveling in pods, these marine mammals have been known to change course in unison in repeated sessions during their travels.
While they tend to shy away from large boats and other scary objects, they display some active behaviors. For example, dolphins that feel they are in a comfortable and safe area may be seen making repeated shallow leaps, breaching the water, spy-hopping, or bow-riding for short distances behind some boats in areas that aren’t overly commercialized. They have also been spotted traveling and interacting with other dolphins in their local habitat.
Some of these other species may include bottlenose dolphins, Fraser’s dolphins, spinner dolphins, and spotted dolphins. Depending on their location, some dolphins have been spotted spending most of their day resting at or near the surface of the water in a fairly inactive manner.
It is suggested that their behavior may differ in different environments based on pod behavior and human interaction. Given their large pod sizes, these marine mammals have also been observed performing large-scale stranding’s where as many as 50 dolphins may end up beaching themselves on land or in shallow waters. Some researchers suggest that noise pollution may cause some of these beachings.
Breeding and Reproduction
The average gestation period for the melon-headed whale is assumed to be around 11 – 12 months. After birth, the female dolphin will nurse her child by feeding it milk until it can hunt and survive independently.
The age of sexual maturity, reproduction habits, and the average number of children that the female melon-headed whale produces are unknown. However, some information suggests that females reach sexual maturity between the ages of 10 – 12 while males apparently reach sexual maturity around 15. These dolphins are believed to have an average lifespan of at least 30 years, with males living 5 – 10 years less than their female counterparts.
Threats and Predators
The melon-headed whale is known to face several humans threats, which may include:
- Bycatch
- Hunting
- Waste/chemical pollution
- Noise pollution
Bycatch– Bycatch occurs when a melon-headed whale swims into a fishing net intended to capture fish (usually on commercial fishing hunts) and gets unintentionally caught in the net where it drowns due to its inability to resurface for fresh air.
In some cases, a dolphin may end assume it has found an easy source of prey (the fish captured in the net), or it may end up swimming into the net because it didn’t realize it was there. In either case, this can lead to death as the dolphin cannot rise back to the surface.
Hunting – It is believed that melon-headed whales may be hunted by poachers interested in either selling their meat for human consumption or using the dolphin’s meat as a form of bait for capturing others ocean prey.
Waste/chemical pollution – In commercial areas, the melon-headed whale may come into contact or be affected by waste and/or chemical pollution. These forms of pollution can directly affect the dolphin’s health, affect the dolphin’s food, or cause complications with reproductive behavior and birth.
Noise pollution – It is often suggested that noise pollution from human-made tools and noisy machinery (i.e., planes, sonar, explosives, etc..) may interfere with the dolphin’s echolocation and sense of hearing. These noises can cause dolphins to lose their sense of direction and may even cause tissue damage to the marine mammal’s ears and brain.
As the earth becomes more noisy, growing concerns regarding the potential effects this is having on marine mammals are continuing to escalate, leading to new research studies on the topic of noise pollution. It is unknown whether these marine mammals face threats from sharks or other large predatory ocean animals regarding natural predators.