January 20 is Penguin Awareness Day - which is not the same as World Penguin Day on April 25. Adelie penguins and all their relatives are so great that someone decided to give them not one but two annual holidays. So in honor of this special day, DW is raising awareness of the adorable, flightless birds.

They can't fly and they're not great at walking either. Despite their fancy tuxedoes, penguins often look slighty clutzy on land. That all changes as soon as they hit the seas. Their streamlined bodies allow them to shoot through water like a torpedo. Even the tallest and heaviest species, the emperor penguins, can swim as quickly as 2.7 (8.9 feet) meters per second.

It seems like an odd combination at first: sand, sun - and penguins? But the birds don't just live in Antarctica. These guys are African penguins. A whole colony of them can be found at Simon's Town in South Africa. Sunny Australia is home to the little penguins. The smallest penguin species grows to be only 30 centimeters (12 inches) tall. Emperor penguins get to be 1.3 meters (4.3 feet).

Here you see an honorary Colonel-in-Chief inspecting his troops. King penguin Brigadier Sir Nils Olav III. lives at Edinburgh Zoo in Scotland. He was knighted in 2008. In 1913, Norway presented the zoo with its first king penguin and in 1972, the King's Guard adopted one: Nils Olav I. He and his two successors at the Edinburgh Zoo have since risen through the ranks from mascot to Colonel-in-Chief.

After oil spills penguins are often cleaned by volunteers. But the gentle hands can't scrub all the oil from the birds' sticky feathers. That's why they put little wool sweaters on the penguins so they don't swallow oil trying to clean their feathers themselves. The oil also destroys the birds' isolating fat layer and the sweaters protect them from the cold.

The cute birds are also successful movie stars. Movies like "The Penguins of Madagascar" and "Happy Feet" were successful animated flicks that featured penguins as protagonists. "March of the Penguins" was a documentary about emperor penguins and the struggles they go through for their chicks. It won the Oscar for Best Documentary Feature.

The film shows emperor penguins during breeding season. The birds walk for weeks from the sea to their breeding spots in the middle of Antarctica's ice dessert. There the male keeps the egg on his feet. The female goes back to sea to eat. The males huddle together to keep warm in the freezing winds. When the chick hatches after 60 days of growing, the father has lost one third of his body weight.

The Bremerhaven Zoo in northern Germany wanted to breed the endangered Humboldt penguins in captivity. But because it's hard to determine the birds' gender, no one at the zoo realized for a long time that most of the animals they had were males. The penguins didn't mind and formed "gay" couples. In the absence of egg-laying females, the homosexual couples tried to hatch stones.

Penguins – a favorite animal for many because of their clumsy, waddling gait – offer researchers a useful way to measure the health of their habitat. Christian Reiss, an Antarctic fisheries biologist at the US-based National Oceanic and Atmospheric Administration, said: "Penguins are great ambassadors for understanding the need to conserve Southern Ocean resources."

Two thirds of the world's 18 penguin species, which range from the volcanic Galapagos Islands on the equator to the frozen sea ice of Antarctica, are in decline, according to a Pew study from 2015. Antarctic penguins in particular are vulnerable to climate change as shifting ice reduces their habitat and warming seas affect their prey.

Scientists blame the decline in penguin numbers on intense fishing pressure on forage species such as krill, as well as pollution, damage to penguin breeding grounds, and climate change. Only two types of penguin – the Adélie and the King - are increasing in numbers, according to the International Union for Conservation of Nature Red List of Threatened Species.

Penguins live most of their lives at sea but return to land to breed and molt. This makes them important gauges of marine health that are easily accessible to researchers, who can then develop conservation strategies. Stanford University marine scientist Cassandra Brooks said: "Scientists need to continue working to untangle the complex interactions between climate change and penguin populations."

The Ross Sea – one of the last intact marine ecosystems in the world, home to penguins – is getting a boost. A deal sealed last year by the Conservation of Antarctic Marine Living Resources - an international group tasked with overseeing conservation and sustainable exploitation of the Antarctic Ocean - will see a massive US and New Zealand-backed marine protected area in the Ross Sea.

The largest of the 18 penguin species found today are emperors. They are around 120cm tall and weigh about 40kg, although their weight fluctuates through the year. But fossils recovered from the Antarctic peninsula reveal that a huge species of penguin which lived around 37 million years ago would have dwarfed emperors – the ancient penguins may have stood 2 meters tall and weighed up to 115kg.

Adélie penguins are one of only five species of penguins that live on the Antarctic continent, the others being the emperor, gentoo, chinstrap and macaroni penguins. Like all penguins, Adélies are excellent swimmers - some have been recorded swimming as far as 300 km (150 km each way) to forage for their chicks.