Dolphins

The best way to see dolphins in Cornwall is via our boat trips of course! A few types of dolphin you may see on your boat trip include Common Dolphins (Delphinus delphis), and Bottlenose Dolphins (Tursiops truncatus) and the more elusive Risso’s Dolphins (Grampus griseus).

As their name suggests, the dolphin you will most likely encounter is the Common Dolphin. Common Dolphins live in pods of around 20 in UK waters and are extremely inquisitive characters. Because of their sociable nature, these dolphins tend to interact with the boats a lot more, giving you an up-close view of their beautiful pod. The Common Dolphin may be easier for you to spot: they can often be seen in their pods following the boats or you’ll see them jumping out of the water as they swim. They have a very distinctive yellow and grey ‘hourglass’ pattern along their sides. Lucky for us, they tend to frequent the deep waters off the Cornish coast, just outside of Padstow!

Yes, dolphins are mammals, specifically marine mammals. This means that they are warm blooded, child bearing aquatic creatures. However unlike land mammals, aquatic mammals like dolphins and whales have a seperate breathing and food passage. This stops them from drowning when hunting and eating their prey. Because of this dolphins don’t actually possess vocal cords and instead uses their nasal passage to produce the distinctive clicks and whistles.

The earliest records of dolphins can be traced back as far as 10 million years. So they’ve been around for a while! Their closest relatives – the whales are even older, existing as far back as 40 million years ago, they lived on land before slowly evolving into the marine mammals we know today. Looking in to the past makes it easier to understand why these exclusively aquatic animals are mammals.

No, dolphins aren’t fish. Although they do spend their entire lives in the water, dolphins still have to breathe air. Fish don’t breathe air or have lungs, they have gills which allow them to take oxygen from the water. Dolphins rely on their blowhole for breathing above the surface. Dolphins are ‘conscious breathers’, meaning they have to think about every breath they take so never fall asleep completely because they’d drown.

Dolphins vertebrae move vertically, similar to our human spines whereas most fish move their vertebrae horizontally (side to side) to move through the water.

Another distinctive quality is that dolphins are warm blooded. Although not all fish are cold blooded, most are because water is a ‘heat sink’ meaning it drains the heat out of surrounding objects which means it takes a lot of energy to stay at a constant heat. Dolphins combat this by surrounding their body with a thick layer of fat (commonly called blubber) which helps them stay warm in the chilly seas!

Almost everywhere! Dolphins live in all oceans of the planet and even in some rivers too. There are 38 types of oceanic dolphins and 4 river dolphin so with 42 different species there’s almost a dolphin for every oceanic environment. One of the best known dolphin (the bottlenose) lives in every ocean in the world – bar the Arctic and Antarctic.

Most dolphins live in the shallow waters, on the ocean’s continental shelves. These areas are generally more productive and have more food than the open ocean, but some of the larger species do venture further out.

They aren’t too picky. Being predators dolphins have to hunt for their food and on average need to eat between 4-9% of their body weight in fish per day. Their diets depend mostly on where they are. In Cornwall dolphins predominantly eat fish like herring, cod or mackerel but may also eat squid or other cephalopods. The largest member of the dolphin family, the killer whale may eat marine mammals like seals or sea lions – sometimes even turtles!

Dolphins use several methods to catch their prey:

• Herding: This is a cooperative hunt performed by a pod. Splitting into two, one group surrounds a school of fish while the other group take turns to eat through the compacted school of fish.
• Corraling: The Dolphins trap fish in shallow waters.
• Stunning: Certain species of dolphins will stun their prey as a method of feeding. When killer whales hunt they tend to use their tails to hit their prey in the water or throw them, stunning them enough to make a fatal blow.

Yes, Killer whales or Orca are often confused with being a whale thanks to their misleading name. Killer Whales are the largest member of the dolphin family with the largest Orca recorded to be 32 feet long and 6 tons! Their distinctive black and white markings vary depending where they live. Like their dolphin relatives, killer whales live anywhere. They’re the most widely distributed mammals (bar humans) on the planet.

Dolphins do sleep but not like land mammals. When it’s time to sleep the dolphin will shut down one hemisphere of it’s brain and close the opposite eye and will alternate this throughout its ‘sleep’. The side of the brain that’s awake monitors the environment and controls breathing. There are three main reasons why they do this:

• This type of sleep allows them to keep moving constantly which helps the warm blooded dolphin to maintain a constant heat.
• To look out for danger and predators.
• If they were fully unconscious they would likely drown because they have to be constantly holding their breath while underwater.