yego.me
💡 Stop wasting time. Read Youtube instead of watch. Download Chrome Extension

Sea Turtles 101 | National Geographic


2m read
·Nov 11, 2024

(Mellow music) - [Narrator] Sea turtles are ancient mariners. Present in all but Earth's coldest oceans, these marine reptiles are well-adapted to a life on the move. (Dramatic music) Sea turtles have existed since the time of the dinosaurs. The earliest known marine turtle lived about 120 million years ago. Named Desmatochelys padillai, it was six feet long and had the characteristic features of modern sea turtles including a carapace, or a top shell, and paddle-like limbs.

Today, there are seven species of sea turtles with the largest being the leatherback. Growing as long as eight feet and weighing up to 2,000 pounds, it is larger than known fossils of its prehistoric ancestor, the padillai. Sea turtles can lay more than 150 eggs at a time. Called the clutch, these large egg deposits help ensure the survival of sea turtle hatchlings. Once a female lays her eggs, she returns to the sea, leaving her hatchlings to fend for themselves.

Fewer than .1% of hatchlings survive to adulthood in part due to numerous predators on the beach. Emerging in large numbers increases the chance that some will survive. (Waves crashing) A sea turtle's sex is determined by temperature. Unlike most vertebrates, a sea turtle's sex is not determined by sex chromosomes. Instead, the temperature of the nest determines the sex of the hatchlings. When temperatures are warm, at about 88 degrees Fahrenheit, most of the hatchlings will be female, but when temperatures are cooler, less than around 82 degrees Fahrenheit, most of the hatchlings will be male.

(Mellow music) Sea turtles use Earth's magnetic fields to navigate. Sea turtles have geomagnetic abilities which serve as an internal GPS. The turtles have particles of magnetite, a magnetic mineral, in their brains. The magnetite likely plays a role in orienting sea turtles to Earth's magnetic poles, similar to a compass. Baby sea turtles imprint on the unique magnetic signature of the beaches where they hatch. This magnetic map can guide them back to the same beaches several years later to lay their own eggs.

(Mellow music) All seven sea turtle species are threatened with extinction. Once abundant, sea turtle populations have dramatically declined in the past two centuries. Fishing is a major threat to sea turtles as they become caught in fishing nets as bycatch, or accidental catch. Illegal harvesting of turtle eggs, trafficking in turtle products, and ocean pollution are also concerns.

However, policies have been enacted to reduce bycatch, protect turtle habitats, and prohibit the killing of sea turtles and their eggs. By continuing this kind of intervention, humans can help stop the decline of sea turtles, helping keep these ancient mariners in the world's oceans. (Waves crashing)

More Articles

View All
Introduction to sampling distributions | Sampling distributions | AP Statistics | Khan Academy
What we’re going to do in this video is talk about the idea of a sampling distribution. Now, just to make things a little bit concrete, let’s imagine that we have a population of some kind. Let’s say it’s a bunch of balls; each of them has a number writte…
Frogs Come Alive After Winter Thaw | National Geographic
NARRATOR: While the rivers and ponds are melting, the ground remains frozen. And under the leaf litter, someone is pulling off a miracle. [intriguing music] This wood frog is frozen solid. Even his eyes are iced over. There’s no pulse, no breath. Slowly t…
10 Low Cost Businesses To Start In A Developing Country
The best way to start making money in a developing country is to start a business for two reasons. One, there isn’t anything much to do anyway; and two, starting a business in that environment is way easier than anywhere else. That’s because all you have …
Angles in circles word problem | Math | 4th grade | Khan Academy
If Ariana turns the stove dial 135 degrees to the right, what setting will the dial be on? So, two very important things up here: first, she’s turning the dial 135 degrees, and which way is she turning the dial? She’s turning the dial to the right. So he…
Wolves vs. Bison: On Location | Hostile Planet
The stars of “Hostile Planet” are obviously the animals. But the unsung heroes are the crew that work so hard to bring you that footage. [wolves howling] PETE MCGOWAN: So my name’s Pete McGowan. I’m here in the Canadian Arctic, trying to film wolves hun…
Dalton Caldwell - Startup Investor School Day 2
Hey, good morning! Thank you. We have a lot to do today, so I’d like to get my part out of the way as quickly as possible. Good morning again, and welcome to our second day of Startup Investor School. My role is a little bit more, but not much more than …