Last night I got to go to the Ocean Film Festival on its stop in Dunedin, NZ on its world tour. Nine phenomenal films, ranging from 2-32 minutes each, covering everything from freediving world records to a somewhat misguided attempt to cross the Atlantic in a two-person rowboat with zero ocean rowing experience. And lots about marine life too – fish, corals, cuttlefish, sea turtles, sharks, whales, manta rays, and more.

I focus a lot on terrestrial (land-based) biodiversity on this site. We humans are terrestrial ourselves, and we tend to focus on what we encounter in our daily lives. But there’s a whole other world of life out there that we don’t usually see – a fascinating, vicious, beautiful world below the waves. Even now, we know relatively little about life in the oceans, despite that it covers more than two thirds of our planet. It’s been estimated by some experts that over 90% of marine life is completely unknown to us.

Even though we don’t know a lot of the life in the ocean, we can still appreciate and protect it, and celebrate the creatures we do know. Thanks to the work of talented filmmakers, photographers, illustrators, and writers, we can all enjoy the hidden ocean world. As marine videographer/photographer Kyle McBurnie says, “Really amazing things happen all the time [in the ocean] … we’re just not there to see them.”

Here in NZ, we’re particularly lucky with our ocean life, especially mammals. NZ has only two native land mammals – the long-tailed bat and the short-tailed bat – but plenty of marine mammals, including 13 species of cetaceans (whales and dolphins) and 4 kinds of pinnipeds (seals and sea lions). Some come down from their territories in the tropics, while others make their way up from the sub-Antarctic seas. Marine mammals have unique adaptations for ocean survival – blubber for warmth, limbs that have evolved into fins, and the ability to hold their breath for long periods. But they have much more in common with us humans than they do with fish – they give live birth, have hair (although only around birth for cetaceans), and are endothermic (warm-blooded).

Here are a few of New Zealand’s most awesome mammalian ocean-dwellers:

The tiny Hector’s dolphins (only 1.5 meters/5 feet long at most) are unique to NZ. Their "mickey mouse" shaped dorsal fins and distinctive black, white, and grey patterns make them easy to distinguish. The only smaller dolphin species is its subspecies, the Maui dolphin, which can also be found in NZ waters and has a similarly rounded fin. Both species are severely threatened by fishing, pollution, and climate change - there are an estimated 10-15,000 Hector's dolphins, and there are fewer than 100 Maui Dolphins (possibly as low as 55 individuals) left in the world. I was lucky enough to see some Hector's dolphin's from a distance along the Catlins Coast over New Years!

The tohora/southern right whale is one of 3 types of baleen whales that frequent NZ seas. Baleen whales feed on plankton by swallowing huge amounts of water, and then strain it through baleen plates, which are feathery sections of keratin hanging down from the upper jaw. The English name for these gentle giants comes from being the "right" whale to hunt, since they're slow, have lots of meat and oil, and float on the surface when killed. They were almost driven extinct, but they're starting to make a comeback.

Sperm whales, on the other hand, are the largest species of toothed whale (dolphins are also technically toothed whales). They don't use their teeth to chew, but to grab it and hold it in place. Sperm whales mostly eat squid, and have been found with sucker marks from giant and colossal squid. They're found around the world, and NZ's population lives near the town of Kaikora on the northeast side of the South Island. There's a deep ocean trench there - sperm whales dive deeper and longer than any other mammal.

The rāpoka/whakahao/New Zealand sea lion is endemic, or only found in NZ. There are about 12,000 of them total, making it the world's rarest sea lion. Their historical threat of sealing was banished more than a century ago, but their numbers remain low due to reproduction problems. There are few breeding populations, and the aggressive males outnumber the females in the extreme. We often get males on the beaches around Dunedin, and people have to be really careful around them!

You can support NZ marine life and conservation efforts through the Department of Conservation. Be sure to check out some of these other ocean conservation groups too!