Ask a biologist what's the most unique animal in all of the Galapagos Islands and the answer most likely given will be the marine iguana. Why? Whilst giant tortoises, sea lions and penguins can be found in other parts of the world, only in the Galapagos will you find this aquatic lizard that is equally at home in water as it is on land.

Easily mistaken for clumps of volcanic rock, the marine iguana spends most of its day basking in the sun to warm up, then once toasty they head in to the water and can dive up to 15 feet to dine on the algae that clings to rocks on the sea bed.

Fully grown iguanas have nothing to fear from predators and are a firm favourite with visitors as they provide fantastic opportunities for an up close encounter. Less can be said about the young whose daunting start in life was documented in BBC's 'Planet Earth II' - upon hatching on Fernadina Island, infant iguanas must run a gauntlet of hundreds of racer snakes who lie in wait on the path to the ocean and safety.

Where to see them:

All over the Galapagos, they can be found in large groups on coastlines where they bask together in the sun. On Espanola Island however you can spot  the "Christmas Iguana", a red and green variation.

You could not have a more emblematic animal to name this very special archipelago after than the Giant Galapagos tortoise. An absolute must see on any trip to the islands they embody the uniqueness of the flora and fauna but also their story tells a much darker tale as well.

These magnificent creatures can live up to 150 years and weigh nearly 600 pounds. You can get an idea of how old the tortoise you are looking at is by examining its shell, older animals have shells that are worn smooth by rubbing against rocks and bushes.

Due to the introduction of predators to the islands by man, baby tortoises are often raised in captivity at the Charles Darwin research centre on Santa Cruz and released when old enough to survive. A visit here gives you a great chance to learn how, adaptating from one common ancestor, the tortoises have evolved into many different subspecies depending on the habitat of their island.

Lonesome George, the very last Pinta Island tortoise who died in 2012, captured the hearts of people around the world as efforts were made to keep his species alive. You can learn about the tortoises intertwined history with man and even pay respects to George himself at the research centre.

Where to see them:

Giant tortoises are now native to seven of the Galapagos Islands, the best chance of seeing them in the wild would be in the highlands of Santa Cruz.

How did a bird that cannot fly end up on an island hundreds of miles from the mainland? Well the answer in truth is that the first ancestors of the flightless cormorants could indeed fly, but a million years in the Galapagos with no natural predators and an awful lot of food in the ocean will make a bird rethink its priorities. Over time their bodies grew bigger and wings became smaller, in fact their wings are now only one third the size that would be required for a bird of its proportions to fly. 

Being another endemic species in the Galapagos, it is one of the worlds rarest birds with fewer than 2,000 in total. You can witness the reversal of mating roles whilst visiting nesting colonies on certain islands with the female deserting the male and the offspring to re-mate with different males.

Where to see them:

West coast of Isabela and Fernandina

You won't find many other creatures with such snazzy footwear as the blue-footed booby. This technicolour bird is native to the Pacific Ocean but up to 50% of the worlds boobies are found in the Galapagos. Their incredibly bright coloured feet and amusing mating dance, during which the male 'dances' with its feet in a up-down motion, creates a comical must see. Above the ocean however, the boobies are grace personified. Watch them perform stunning dives into the ocean to catch fish.

Where to see them:

Found throughout the Galapagos but main breeding colonies on Espanola and North Seymour.

One of the rarest birds in the world, found only on Espanola Island, where you can see them engage in sword fights with their bills and listen to the tap dance like clacking sound they make in breeding season. They do this ritual as it creates a unique dance that allows them to recognise each other year after year as they return to the same island.

Often referred to as the 'Waved Albatross', down to the pattern on their wings, they are endemic to the Galapagos. What makes them different is that they don't create a nest for their eggs, instead they roll, yes roll, their egg 50 metres or so around the island. No one is sure as to why but if the worst was to happen and the sole egg laid that year breaks, there are rare cases of Albatross divorce where breeding pairs separate never to mate again.

Galapagos albatross do have a very predictable breeding cycle, and with good reason: if the birds have not left the island with their hatch-lings by mid January, they would be stranded due to the lack of wind needed for them to soar. Once up however they can stay airborne for hours thanks to their 8 foot wingspan!

Where to see them:

Espanola Island.

Penguins on the Equator? Absolutely. Initially built for colder climates the Galapagos penguins are the only ones to have adapted in order to survive this far north and of the 18 species of penguin, they are the rarest.  They look very similar to their mainland relatives from whom they originated being dragged over on strong currents from Chile and Peru. There are however a few differences, the Galapagos penguin is the second smallest in the world and also doesn't have a specific mating season, their breeding depends on water temperatures and food supply.

Appearing clumsy on land at first, they are excellent swimmers, their grace and speed can be fully appreciated by joining them in the water whilst snorkelling.

Where to see them:

Mainly on Fernandina and the west coast of Isabela

Most Galapagos cruises will have you landing on beaches where you are likely to encounter one the archipelagos friendliest residents, in fact it doesn't even have to be a beach, in the town of Puerto Ayora on Santa Cruz Island you will see them sleeping by the shore in the midday sun.

Galapagos sea lions are much smaller than their mainland cousins but what they lack in size they make up for in personality. These mischievous creatures are best experienced in the water whilst snorkelling as they can show off their acrobatic abilities and playfully blow bubbles at you.

There are both Galapagos sea lions and Galapagos fur seals lying on the beaches which you will encounter, so how do you tell the difference? Well sea lions have the ability to prop themselves up on their front flippers, something that the Galapagos fur seal cannot manage. Also sea lions have exterior ear lobes so when you see heads bob above the waves you can quickly tell between the two.

Where to see them:

They can be found on every island in the archipelago.

When Charles Darwin spent a month in the Galapagos, initially he didn't think much of these little creatures, describing them as “drab and dull little birds” and you may at first think the same way. But first impressions can be deceptive and what makes the 13 remaining species of finch so special are their beaks and what they mean for science.

The differing sizes of beaks belonging to these finches baffled Darwin at first and it wasn't until his return to London that it was discovered that his specimens were all related. In truth the finches had adapted to individual habitats on each island and he used his findings as clear evidence towards his theory of natural selection and evolution.

These finches have changed the way we understand the world around us and even today they are considered as the world's fastest evolving vertebrae. So if you are lucky enough to spot these "drab" little birds, take a moment and appreciate the differences that makes them so unique - just like Darwin did all those years ago.

Where to see them:

They are spread amongst various islands with some species found solely on one island (make sure you take binoculars!)