And I don't know about you, but watching Katmai crunch down on her Olympic gold medal ice treat kind of made my teeth hurt. So I thought that'd be the topic of this week's Deeper

我不知道你們怎麼想，但看著卡邁咬著奧運金牌冰激凌，我的牙都疼了。所以，我想這就是本週 "更深入 "的主題。

Dive. Teeth. Don't forget to like, subscribe, and head down to the descriptions below for ways that you can help support the channel. It's no secret that animals have special adaptations to allow them to survive in their specific ecological niche. One adaptation is teeth.

潛水。牙齒。別忘了點贊、訂閱，並在下面的說明中找到您可以幫助支持該頻道的方式。動物有特殊的適應能力，以便在特定的生態環境中生存，這已經不是什麼祕密了。牙齒就是其中之一。

Also, dentition is widely determined by specialized feeding habits. Let's start with sea otters. If you're a fan of this channel, then you probably know that sea otters love to eat. They typically prey on mollusks like oysters or clams, even echinoderms like sea urchins, or invertebrates like shrimp or crabs. And what do all of these animals have in common? An exoskeleton, or a hard shell. I'm going to assume that most of you already know that sea otters use tools like a rock to crack into hard shells, in a motion similar to what Katmai is doing here in this clip. But what if we don't have a rock? Sometimes, sea otters will just use their teeth.

此外，牙齒也是由專門的進食習慣決定的。讓我們從海獺開始。如果你是本頻道的粉絲，那麼你可能知道海獺愛吃。它們通常捕食牡蠣或蛤蜊等軟體動物，甚至海膽等棘皮動物，或蝦蟹等無脊椎動物。這些動物有什麼共同點呢？外骨骼，或者說硬殼。我想你們大多數人都知道海獺會用石頭之類的工具敲碎硬殼，就像片段中卡特邁的動作一樣。但如果我們沒有石頭呢？有時，海獺會直接用牙齒。

That's the kind of stuff that would probably make a dentist cringe. But sea otters have adaptations that make this no big deal. Their molars have six roots instead of four, like ours, and they're flat and rounded, perfect for crushing. Sometimes, wild otters will even eat some of the shells. This not only provides them calcium, but something called roughage. It's very good for the digestive tract. Taken from someone who has cleaned up their fair share of otter poop, it is unique. So unique that it has its own name, Sprite.

這種事情可能會讓牙醫感到恐懼。但海獺的適應能力讓這沒什麼大不了的。它們的臼齒有六根，而不是像我們一樣的四根，它們的臼齒又扁又圓，非常適合碾碎。有時，野生海獺甚至會吃掉一些貝殼。這不僅為它們提供了鈣質，還提供了一種叫做粗糧的東西。這對消化道很有好處從一個清理過水獺糞便的人口中得知，這種糞便很獨特。獨特到它有自己的名字 雪碧

Back to teeth. Let's talk about the most unique tooth in the ocean, narwhals. Also known as the unicorns of the sea because of their most impressive asset, their tusk. These tusks are actually a canine tooth that projects from the left side of the upper jaw through the lip and forms a left-handed helix spiral. Some males, about 1 in 500, actually have two tusks. Scientists are still debating and searching for the biological function of the tusk. And while the answer is still unknown, the leading theory is that it's somehow involved in a mating or breeding display because of the fact that males tend to have them more often than females. However, recent analysis has shown that the tusk is a highly innervated sensory organ with millions of nerve endings. So, it appears that this tusk is some sort of sixth sense that helps the animals feel around their dark, wintery, cold world. There are very few tusked animals in the world and only one other tusked marine mammal. It just so happens to be my favorite animal of all time, the walrus. Just like narwhals, the tusks of the walrus grow throughout their lives. They're basically modified canine teeth. They can reach about a meter in length and the root of that tusk grows very close to the sinuses in the walrus. The depth of these canine roots makes dental health for walruses extremely important because they can easily break or chip tusks. And if those tusks get a break or a chip, an infection, an abscess, that infection can very easily make its way up to the sinus and even into the brain. In the beginning of the video,

回到牙齒。讓我們來談談海洋中最獨特的牙齒--獨角鯨。獨角鯨也被稱為海洋中的獨角獸，因為它們最令人印象深刻的資產就是它們的獠牙。這些獠牙實際上是一種犬齒，從上頜左側伸出，穿過嘴脣，形成左旋螺旋狀。有些雄性（大約五百分之一）實際上有兩顆獠牙。科學家們仍在爭論和尋找象牙的生物功能。雖然答案仍是未知的，但主要的理論認為它在某種程度上參與了交配或繁殖的展示，因為事實上雄性往往比雌性更經常長出象牙。然而，最近的分析表明，長牙是一個高度神經支配的感覺器官，有數百萬個神經末梢。是以，這種長牙似乎是某種第六感，可以幫助動物

I mentioned that teeth usually have specialized functions. Most people assume that the specialized function of a walrus tusk is for fighting or sparring, but unlike narwhals, all walruses have tusks, even all the females. Walruses use their tusks as levers to basically pull their hulking bodies out of the water. Walruses are the heaviest member of the pinniped family.

我提到過，牙齒通常有專門的功能。大多數人都認為海象的獠牙的特殊功能是用於戰鬥或格鬥，但與獨角鯨不同的是，所有的海象都有獠牙，甚至所有的雌海象都有。海象用它們的象牙作為槓桿，將自己龐大的身軀拉出水面。海象是有脊柱動物家族中最重的成員。

This is a family that includes animals like seals and sea lions. Most pinnipeds have a unique bacteria that lives on their teeth that can cause an infection in humans called seal finger. This is something I've covered in a previous video, and if you're interested, you can find it right up here. However, I have gotten a lot of comments here and over on my Twitch channel about how we take care of animals' teeth when they live under human care. Do our animals go to the dentist?

這個家族包括海豹和海獅等動物。大多數針足類動物的牙齒上都有一種獨特的細菌，這種細菌會導致人類感染海豹指。這是我在以前的視頻中講過的內容，如果你感興趣，可以在這裡找到。不過，我在這裡和我的 Twitch 頻道上收到了很多關於動物在人類照顧下如何護理牙齒的評論。我們的動物會去看牙醫嗎？

Dental care is just as important to animals under human care as it is to people. We check their mouths every day to make sure that everything is looking good. In most of our critters, a basic open mouth present is one of the very first things that they learn. Going a step further, we can even train the animals to allow us to brush their teeth or even use a water pick to make sure that they're looking clean and healthy on a daily basis. Every animal typically gets a yearly physical from our veterinarians, and this includes a dental checkup and clean. If necessary, animals can even have a tooth pulled, like my favorite California sea lion, Senor Cinco. You can see here he's missing his bottom left canine. That was an unfortunate, unnecessary, human-caused injury of a gunshot wound. With walruses and their incredible tusks, we'll use caps. If you recall earlier, I talked about how walruses used their tusks to help them pull their enormous bodies out of the water. This, of course, causes a lot of stress on the tusk that could potentially cause injury. Often with walrus under human care, we'll put a cap on the end of their tusk that prevents them from getting damaged in the first place. In this clip, you can see me applying a cap to a very awake, very feisty baby walrus.

牙科護理對於接受人類護理的動物和人類一樣重要。我們每天都要檢查它們的口腔，確保一切正常。對於我們的大多數小動物來說，基本的張嘴是它們最先學會的事情之一。更進一步，我們甚至可以訓練動物讓我們為它們刷牙，甚至使用水鎬，以確保它們每天都保持乾淨健康。我們的獸醫通常每年都會為每隻動物進行體檢，其中包括牙齒檢查和清潔。如有必要，動物甚至可以拔牙，比如我最喜歡的加州海獅 Senor Cinco。你可以看到它左下方的犬齒不見了。這是一個不幸的、不必要的、人為的槍傷。對於海象和它們令人難以置信的獠牙，我們將使用帽子。如果

And that brings us back to sea otters. I mentioned that sea otters will often use their teeth to crack into hard shells. This actually helps scrape the plaque away from their teeth, keep their gums healthy as well. And this is one of the reasons that we give them ice treats. To be honest, one of the main reasons we give sea otters ice treats is because they love it. And if you'd like to see more of that, click on the shameless suggested link at the end of the video. But we also do it because ice simulates those hard shells. Crunching through that ice actually helps to remove regular buildup of plaque on sea otter's teeth. Honestly, teeth are so important, I could probably go on forever about them. I definitely didn't cover everything I wanted to. So if you have any questions, definitely drop them in the comments below or head over to my Twitch channel where I can answer them live. But for now, enjoy some clips of otters enjoying their ice treats with their impressive teeth, and I'll catch you next time. Cheers!

這又回到了海獺身上。我提到過，海獺經常用牙齒咬碎堅硬的貝殼。這實際上有助於刮除牙菌斑 保持牙齦健康這也是我們給它們吃冰的原因之一。老實說，我們給海獺吃冰的主要原因之一 是因為它們喜歡吃冰如果你想了解更多，請點擊視頻末尾的無恥建議鏈接。但我們這樣做也是因為冰能模擬海獺的硬殼。咬碎冰塊實際上有助於清除海獺牙齒上經常堆積的牙菌斑。老實說，牙齒非常重要，我也許可以一直講下去。我肯定沒有把我想講的都講完。所以，如果你有任何問題，一定要在下面的評論中提出來，或者去我的 Twitch 頻道，我可以現場回答你的問題。現在

Thank you. Cute. He's like, I got you one clam treat!

謝謝。真可愛他說，我給你買了一個蛤蜊！