Smart but Unpopular Species of Sunderbans

Gautam Kumar Das

Mudflats, natural levees and river banks of the Sunderbans are the habitat of some animals, very much uncommon to the people in general for years, but the inhabitants of the Sunderbans are habituated to see them all knowingly or unknowingly. These interesting but least understood animals are represented by some species, known of late, throughout the Sunderbans. The estuarine deltaic plains of the area seem to harbour a rich and varied fauna, though much attention has not given to them either by the visitors of the Sunderbans or by the people any way interested about the Sunderbans. Therefore, they are uncommon, unpopular and even somehow unknown fauna, but they are unstoppable in generating attention and curiosity, so they are simply smart in appearance.

Among the faunal assemblage in the Sunderbans, mud skippers, the air breathing fishes, are looking very smart. They sink all on a sudden inside the mud digging into it when they found anybody else outside of their community. They belong to the family Gobiidae and are abundantly in the tidal flats or river banks of the Sunderbans. Mud skippers feed only during the ebb tide when the mudflats are completely exposed. They display thus, a very conspicuous biological clock as they appear only in the rhythmic tidal cycle of the dynamic estuarine environment.

King crab couple, in ecstasy, comes in pair during the breeding season drifting in the high tidal waters. A small size male likes a large size female and the bigger female usually carries a relatively smaller male on her back. On contrary, the male remains attached with the female’s opisthosoma with his modified legs. After arrival to a mudflat or sand flat, they can venture the same ground for looking a suitable place befitted for their copulation. Comparatively bigger female digs a burrow and lays her eggs in cluster and the male sheds sperms upon the eggs finally, makes possible of external fertilization that leads to reproduction. Thus, king crab couple, only available in nature in their breeding season, is seen hugging of male with the female that begins in mid February and lasts up to June-July. Perhaps king crabs observe valentine day as they fall in love on the second week of February.

Sometimes hugging is not for making love, particularly when snails hug the mussels in the river flood plain or upon beach of the bay. Snails in majority, intrude through the mud and trail like ploughing, find mussel and hug them. Several snails feed usually on mussels, boring through one valve by a combination of chemical and mechanical activity so that some of the organs like proboscis and radula can be inserted and the mussel tissues torn out. First the snails grip the mussel tightly with their mantles. They then soften the area tightly gripped spraying the mucous materials of their own. Snails exert pressure then with the radula at the softened part (with the application of mucous) of the shell of the mussel after being applied with the mucous materials and ultimately a small pore formed. The snails then enter their proboscis into viscera of the mussel through the pore they already made and start sucking all of the flesh of the entire mussel. In this way some snails boring species cause remarkable damage to mussel beds. Almost all the shells of the mussel scattered in the sand flats or sea beach are visible with these types of small pores as a consequence of being eaten up by the snails of the same phylum mollusca.  

Mudflats along the river banks support numerous diversified species populations like sea cucumber, sea pen, sea anemones etc. A majority of the intertidal mud-dwelling animals prefer such low-salinity water situations where environmental conditions are marked by different from those of terrestrial or fresh water habitats. Animals in such habitats acquire a certain degree of adjustment or adaptation as insurance against every oscillating environmental condition. Sea cucumber prefers such habitat. These animals are categorically classified as holothuroid under the phylum Echinodermata. They are covered with minute spiny projection all over their body surface and contain five stripes in total over their body surface looking almost like a cucumber. <ektitashabits. Sea cucumber is a benthic dweller over mud surface when their habitat is inundated with the tidal water and it enters inside the mud layer when water recedes during ebb tide. Sometimes feather-like projection is scattered in some mudflats and the entire animal is seen if it is pulled very softly or sorting out the animal after washing the uplifted lump of mud containing the animal with the river water. The animal looks like a feathered pen that once used by the poets of the medieval era. Certainly these animals are called as sea pen and they are Cnidarians. In addition to the sea pen, enormous sea anemones are available in the same habitat of sea pen which is looking like sun flowers as their tentacles are arranged radially. If somebody likes to touch them, they spray immediately chemically poisonous cnidoblasts cells and the touched portions are felt with burning sensation. Sea anemones are stationary animals, only able to move their tentacles, but never drift or go to the other places from their places of brought up. All these species are not known to the most of the people, they are simply unpopular. But Sunderbans are known for its common species that make the Sunderbans beautiful when the banks of the rivers are inundated with semidiurnal tides, skylark floats with the ripples of river waters, bioluminescence of Noctiluka of the river water blazes all on a sudden in the gloom deeper at winter night. Sunderbans is excellent for its amazingly quiet nature and simultaneously it is awe-inspiring abode of Royal Bengal Tiger, estuarine crocodiles, king cobra or pythons. Here amazingly quiet environment of grand symphony of silence is uninterrupted. Wild bees in swarms come to khalsi bushes of Sunderbans during spring to produce honey and wax and cause pollination. Monkeys cover their bodies with muddy clays before tasting that honey. Kaora tree opens its petal of flowers with tens of stamina to tempt the bats to feed on and ensure pollination. The snails crawl to climb up trees, the animals quench their thirst by drinking salty water, and the roots of some mangroves grew upwards in direction to that of centre of gravity and make shelters of the several brackish water snails.

Oct 6, 2018

Gautam Kumar Das [email protected]

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