Intertidal Walk in Havelock Island, Andaman

What is the intertidal zone?

The intertidal zone is the band of shore that sits between the highest point the tide reaches and the lowest point it falls to. It is the only habitat on earth that is a sea for part of the day and dry land for the rest of it.

That is a demanding place to live. Everything there spends part of the day submerged in salt water and the rest of it out in the sun, the heat and the rain. On top of that, predators arrive from the sea at high tide and from the land and the sky at low tide. What survives all of that carries some of the cleverest equipment on the shoreline, packed into a strip you can walk across in a minute.

The four bands, from dry to wet

Walk down a shore at low tide and you cross four zones. Each one is under water for a different amount of time each day, and each has its own residents.

What you may find on a Havelock shore

Nothing on a shoreline is guaranteed, and that is half the reason it holds your attention. Over a typical walk, though, these are the animals that turn up most often:

• Crabs. Hermit crabs dragging borrowed shells, ghost crabs sprinting across open sand, porcelain and rock crabs wedged into crevices.
• Sea slugs and nudibranchs. Slow, and often far brighter than anything else on the shore. The colour is usually a warning that they taste terrible.
• Brittle stars, relatives of the starfish with long whip-like arms, usually under stones. Grab one and it sheds an arm, then grows a replacement.
• Sea cucumbers. Unglamorous, and doing more work than almost anything else on the shore. They process sand the way earthworms process soil.
• Molluscs: cowries, top shells, nerites, and chitons clamped flat to the rock.
• Anemones and small fish. Anemones pull shut into blobs of jelly at low water, and gobies and blennies sit out the low tide in the pools.
• Sea urchins, usually in the lower band and tucked into hollows. Worth learning to spot, mainly so you do not stand on one.

Tide pooling rules that actually matter

A tide pool is a small, crowded place, and it is easy to do damage without meaning to. These are the habits your guide will ask you to keep. They are worth carrying to any shoreline you ever walk on:

• Put every rock back exactly as you found it, same side up. The underside of a stone is somebody's roof, and flipping it and leaving it kills what was living there.
• Wet your hands before you touch anything, and keep it brief. Dry, warm hands damage the skin and mucus layer of soft-bodied animals.
• Leave the animal in its pool. Moving it to a nicer-looking pool for a photograph usually means putting it in the wrong zone.
• Do not handle cone shells. Cone snails carry a venomous harpoon and some species in this region are dangerous to people. They are attractive, which is exactly the problem. Look, photograph, do not pick up.
• Do not collect shells that still have an animal in them, and remember a hermit crab is walking around inside a lot of what looks empty.
• Watch the water, not just the pools. The tide turns while you are looking down. Your guide keeps track of it, but it is a good habit to build.

What your ₹2,000 covers

What to bring

• Water
• Insect repellent
• A cap or hat, and sunscreen
• Footwear you do not mind getting wet or muddy, with a sole that grips. Wet rock is slippery and broken shell is sharp
• A phone or camera if you want photographs, though you will be using your hands

Avoid anything you would be unhappy getting dirty. You will be walking on wet ground and crouching next to pools.

Weather, tide and rescheduling

• We confirm the start time the day before, once we have the tide for your date.
• If the weather makes the shore unsafe or the tide is not low enough to be worth it, we move you to another slot during your stay.
• If no suitable slot is available before you leave, we refund in full.
• If you cancel 72 hours or more before, you get a full refund minus a 5% fee and GST. Inside 72 hours there is no refund. Walks between 15 December and 15 January are non-refundable. See our refund policy.

The walk pairs well with our other land-based experiences, especially the mangrove walk, which is also timed to the tide, and stargazing in the evening.

Intertidal walk in Andaman: frequently asked questions