A Gallery of Dolphins Trivia Quiz

Answer: False

Probably the most well-known of their kind, bottlenose dolphins are noted for their high intelligence, and like a number of very smart animals have been seen improvising tools in the wild. Specifically, dolphins in Shark Bay, Australia, have been observed to cover their beaks with marine sponges before looking for food hidden on the seafloor.

It is thought that the sponge is to protect the beak from sharp spines and stings. Furthermore, dolphins have been shown to learn this behaviour by copying it after observing other dolphins; in particular, the behaviour, which is more common in females than males, has been passed on from mother to daughter.

In addition to using sponges, bottlenose dolphins have been observed using large conch shells to trap fish inside while underwater, then raise the shells above the water and shake the fish out into their mouths.

Answer: Largest species of river dolphin

Also known as the pink river dolphin because of its striking colour, the Amazon river dolphin is the largest river dolphin but not the largest of all dolphins. It is found throughout the waterways of the Amazon basin and other nearby rivers. The species is strongly sexually dimorphic, with adult males being about 16% longer and 55% heavier than females. Specifically, adult males have an average length of 2.32 metres and weight of 154 kilograms, while adult females are about 2 metres long and weigh 100 kilograms on average. Males are thought to compete fiercely for females during breeding season, and frequently display bites and abrasions over much of their body.

These dolphins eat up to 53 species of fish (including piranhas!), as well as other animals such as turtles and crabs. Currently, they are classified as endangered, as they are under threat from habitat loss, entanglement in fishing lines, and competition for food from fishermen.

Their life expectancy remains unknown, although one individual in a German zoo lived for over 46 years.

Answer: Shallower, warmer coastal waters

The long-beaked common dolphin is a medium-sized dolphin notable for its striking coloration, having a dark coloured back and a white belly, with an hourglass pattern on its side that varies from light grey, yellow or gold in front and dirty grey in back.

Its preferred range tends to be somewhat restricted as they prefer to stay near shore in shallow, warm waters. However, they are also widely distributed, being found off the coasts of parts of north and South America, Africa, and Asia. They are highly gregarious and may swim in pods of hundreds or even thousands of individuals.

They have also been observed to swim with other cetaceans such as bottlenose dolphins and pilot whales. They are also noted for playful behaviour such as bow riding, i.e. body surfing waves created in the wake of baleen whales and boats, as well as jumping into the air in acrobatic displays. Like a number of other species, they engage in cooperative hunting in which they drive prey into a ball formation.

Their moderately long snout contains 47 to 67 pairs of small sharp teeth in each jaw, more than any other dolphin species. Like many other dolphin species one of the major hazards they face is entanglement in fishing gear such as driftnets and longlines.

Answer: Dusky dolphin

Dusky is Latin for "dark" or "dim"; the species name "obscurus" is also Latin and has a similar meaning. The dusky dolphin has quite distinctive colouration, being dark grey or black on the back, including a short dark beak and dark patches around the eyes that give them the appearance of wearing eyemasks.

The belly is white, and the sides are grey. This species is regarded as the most energetic of all dolphins, as they are noted for being very active and fast moving, and display spectacular, highly coordinated acrobatics, including high leaps and twists performed in groups. Apart from the sheer fun of doing it, this behaviour appears to help them synchronise their cooperative movements to herd prey, as they can see each other easily when in the air. Dusky dolphins are found in the southern hemisphere in cool coastal and temperate waters, off New Zealand, South America, southwestern Africa and around some oceanic island groups.

They are highly sociable, and their group sizes range from about 20 or so to sometimes a 1000 or more.

They are a protected species throughout much of their range, although their conservation status is not entirely clear because of insufficient data.

Answer: The only dolphin that swims on its side

There are two varieties of the South Asian river dolphin - the Ganges river dolphin that is primarily found in the Ganges and Brahmaputra rivers, and the Indus river dolphin that is found only in the Indus River in Pakistan - and these are thought to be subspecies of a single species.

The South Asian river dolphin is the only cetacean known to swim on its side, and for this reason is also known as the side-swimming dolphin. The dolphin's eye lacks a lens, which means that it cannot form clear images on the retina, rendering it nearly blind, although it can usefully detect changes in lighting. Because of its poor vision it mainly relies on echolocation to navigate and find prey. Like all river dolphins, it has a long, pointed beak, which is useful in locating hidden or hard-to-find prey items, including shrimp, fish, and occasional birds and turtles.

Despite being a protected species, it is currently endangered, facing threats from river pollution, damming of rivers that restricts its range, and illegal hunting.

Answer: Fighting with each other

Risso's dolphins have a very distinctive appearance as they have very stocky bodies for a dolphin, a blunt head, and no visible beak. Calves are born with grey or olive brown skin but as they mature, they become increasingly pale, which seems to be a result of permanent scarring acquired over a lifetime that causes gradual loss of pigmentation.

Although most cetaceans show some scarring, Risso's dolphin seems to have taken this to the extreme. Researchers who study them can actually identify specific individuals by their scarring patterns.

This species does not require its teeth for feeding, so evolution has turned their teeth into weapons that they use in disputes with each other. It has been theorized that the scarring acts as a threat display to others as a signal of the individual's fighting prowess and the loss of pigmentation over time may be an evolved trait to display their scars more prominently.

Although what I have described so far might make it sound like they are constantly at each other's throats, like other oceanic dolphins, they are a highly social species and have been known to swim in super-pods of hundreds or even thousand of individuals, and to interact with other species of dolphins and whales.

Answer: True

This small species is recognisable for the colourful stripes that run the length of its body. They range throughout the world's temperate and tropical oceans and prefer deeper more offshore waters. They are energetic, fast swimmers and travel in large groups, often up to thousands at a time.

Although an abundant species, they are classified as "conservation dependent," meaning that without active conservation efforts their survival would be threatened. Not helping matters is that in Japan, they are one of the main species targeted in the annual Taiji dolphin drive hunt, one of the world's largest such hunts, that occurs from September to February in a famous whaling town. Captured dolphins are mainly killed for their meat, although a few are selected for captivity and sold to marine parks.

The World Association of Zoos and Aquariums prohibits member organizations from purchasing dolphins captured this way, but unfortunately there are many marine resorts that are not members. It is also worth noting that dolphin meat contains dangerously high levels of mercury, so consuming it is foolish as well as cruel.

Answer: Tuna fishing

As its name suggests, the pantropical spotted dolphin is found throughout the tropical and temperate waters of the world's oceans. They have a habit of swimming with tuna, particularly in the eastern Pacific Ocean, not because they eat them, but because they prey on many of the same fish.

This was nearly their undoing because of the once widespread use of purse seine nets to catch tuna that would result in the capture and deaths of millions of these dolphins. At one point about half of their world population was believed to have been wiped out. Fortunately, public awareness of the plight of these animals led to the development of "dolphin-friendly" methods of catching tuna, and the species has rapidly recovered.

As their name suggests, most adults are covered in spots and individual dolphins can be identified by their distinctive markings, although there are regional differences between subpopulations, with some groups having few or even no spots.

Infants are born with a uniform colouration that makes them look more like bottlenose dolphins, and they gain more spots with age. Known for their acrobatics, they are highly sociable and frequently swim with other species such as spinner dolphins.

Answer: Killer whales in the wild have caused many human fatalities

Although killer whales in the wild have occasionally been known to attack humans, there are no recorded cases of resultant human fatalities. On the other hand, attacks by captive killer whales in marine parks have occasionally caused human deaths. For example, there was a shocking incident in 2010 at SeaWorld Orlando during a live show in which a killer whale grabbed a trainer's ponytail and dragged her underwater until she drowned. Killer whales are known to prey on a wide range of cetaceans, including large species such as minke and grey whales; there have even been rare reports of them attacking sperm whales and blue whales in which they have usually targeted calves or wounded animals.

For example, scientists tracking sperm whales in the Galapagos Islands in 1985, witnessed an attack lasting nearly two hours on a group of about 30 sperm whales by about 15-25 killer whales.

Although several of the sperm whales received bloody cuts, these did not appear to be serious wounds, and none of them were killed; no injuries to the killer whales were observed.

The scientists who witnessed this attack suggested that the killer whales may have been probing the sperm whales' defences for signs of weak individuals, or alternatively the encounter may have been for practice or play by juvenile killer whales, who were the main attackers. Sperm whales make formidable opponents, as they have teeth and large flukes, so killer whales are not generally a major threat to them. As to land animals, killer whales are known to attack deer swimming between islands off the northwest coast of North America. Regarding cooperative hunting with humans, there is a well-known case in New South Wales, Australia, during the 1800s in which killer whales cooperated with whalers for 80 years in hunting humpback and right whales. After the kill, the whalers allowed the killer whales to feed on the lips and tongues of the dead whales, as these parts were less commercially valuable. The whalers would reclaim the whale carcass the next day.

Answer: False killer whale

Because of similarities in the skull between this species and killer whales, it was once classified with the genus name Orca, which is another name for the killer whale. Subsequent examination of the bodies of stranded specimens showed that it was not a true killer whale, so it was decided to give it a new genus name, Pseudorca, meaning "false orca," hence its common name. Like the killer whale, though, it is considered to be more closely related to oceanic dolphins than other whales. False killer whales are a highly social species and often have friendly interactions with a variety of dolphin species, including bottlenose dolphins, and are even known to respond to distress calls from other species and to protect them from predators.

In fact, they may even go so far as to have sexual relations with bottlenose dolphins, with members of both the same and opposite sex.

These unions (well, the heterosexual ones at least) sometimes produce hybrid offspring known as "wholphins," which are fertile.

Although they mostly eat fish and squid, they occasionally prey on other cetaceans, including humpback and sperm whales (!) as well as smaller dolphins (I don't know how their other dolphin friends feel about this). False killer whales can be quite friendly to humans and sometimes offer fish to divers and people on boats. Additionally, they do well in captivity and are highly trainable (not that I condone keeping them in captivity).