Sea Snakes Part One: Introductory

1. Number of species: 55-62 depending who you ask

2. Most, if not all, snakes can swim. SSSSSERPENTINE MOTION

3. True sea snakes and Sea kraits Laterally flattened body, (including tail) Give birth at sea Reduced or no scales on belly Main body is cylindrical, only the tail is flattened Give birth on land Scales on belly

Anatomy & Physiology Adaptations: Flattened body Valvular nostrils Salt glands Loss of scales on belly Elongated lung Ability to absorb oxygen through skin

2. A keel? Fin-like structure that provides surface area. This enables propulsion by lateral undulations.

To review: a. American eel: a snake-like fish (elongated) b To review: a. American eel: a snake-like fish (elongated) b. Sea snake: a fishlike snake (laterally flattened) c. Terrestrial snake: a snake-like snake

3. Sea snake scales Terrestrial snakes have scales that overlap (“dragon scales”) Sea snakes have scales like a tile floor

Diffusion of dissolved oxygen through skin 4. Sea snakes can hold their breath for two hours at least. Also, they can perform CUTANEOUS RESPIRATION: Absorbing up to 33% of their oxygen needs through their skin. Diffusion of dissolved oxygen through skin

5. Snake lungs All snakes have an asymmetrical pair of lungs 5. Snake lungs All snakes have an asymmetrical pair of lungs. As they evolved their elongated form, their internal anatomy modified so that one lung (the right one) grew and the other (the left one) shrunk. In sea snakes it’s the same, just more extreme, with the right lung almost as long as the entire body.

No me gusta la tierra 6. True sea snakes struggle to move on land. The lack of belly scales removes traction, and the flattened body shape practically makes them topple over.

Sea kraits, on the other hand, can move on land. I ONLY HAVE A LATERALLY FLATTENED TAIL!

7. See Part One, number 3

Part Three: Ecology

1. Where in the world can you find sea snakes? In all the blue band (warmer waters.) Interestingly they’re completely absent from the Atlantic, except that one little area where some have snuck through the Panama canal.

2. They prefer shallow coastal water because they often feed among coral reefs (which depend on shallow, sunlit areas.)

3. An exception: The yellow-bellied sea snake is the only open ocean species

4. A mostly piscivorous diet

5. The sublingual (under the tongue) salt gland excretes excess salt SQUIRT

6. The color combination of red/orange/yellow with black/dark brown is universal for poisonous to eat, or “I have a venomous bite.”

7. Okay, Señor Robles is out of time. You’re on your own for the rest 7. Okay, Señor Robles is out of time. You’re on your own for the rest. Good luck!

Time to learn https://m.youtube.com/watch?v=0rqcigdJi3o