Consider the following statements regarding the ‘Gangetic Dolphin’ :
1. The Gangetic River Dolphin has been categorized as ‘endangered’ under the IUCN’s Red List.
2. It does not have a crystalline eye

Question

Consider the following statements regarding the ‘Gangetic Dolphin’ :
1. The Gangetic River Dolphin has been categorized as ‘endangered’ under the IUCN’s Red List.
2. It does not have a crystalline eye lens rendering it effectively blind.
3. Navigation and hunting are carried out using echolocation.
4. It has been recognized as India’s National Aquatic Animal.
Which of the above statements are correct?

UnlockIAS · Accepted Answer

Correct — D, All of the above. Every one of the four statements survives a check against the Wildlife Institute of India, the MoEFCC's own autonomous institute — though one of them needs a careful word about how it is phrased. Statement 1: WII's species page records that Ganges river dolphins "are listed as Endangered in IUCN red list", citing the 2022 assessment of Platanista gangetica (Kelkar, Smith, Alom, Dey, Paudel and Braulik, IUCN Red List of Threatened Species 2022, e.T41756A50383346) — Endangered exactly, one rung below Critically Endangered and one above Vulnerable. The same page supplies the number that makes the category intelligible: "Their population is estimated to be less than 2000 individuals." It also records Schedule I of the Wild Life (Protection) Act, 1972 and Appendix I of CITES, and the species additionally sits on Appendix II of the Convention on Migratory Species. Statement 2 is the one to be precise about. WII's National Mission for Clean Ganga species page states that "the Gangetic dolphins can only live in freshwater and are essentially blind", and that functional claim — the animal cannot form an image and is effectively blind — is what statement 2 asserts and what makes it correct. The mechanism the stem supplies, the absence of a crystalline eye lens, is the standard scientific account of why, but it deserves an honest flag: no government page reachable while building this card uses the words 'crystalline lens'. WII writes "essentially blind"; WWF-India's species page writes "generally blind". So take the blindness as government-sourced and the lens detail as the textbook explanation behind it, rather than as an official form of words. Either way statement 2 is not the false one in the set: the eye is tiny, lacks the image-forming optics other cetaceans carry, and registers little more than the direction and intensity of light in water so silt-laden that sight would buy nothing. Statement 3: the same WII page says they "hunt by emitting ultrasonic sounds waves that bounce off of fish and other prey", and WII's Endangered Species Recovery Programme page credits them with "a highly developed bio sonar system that facilitates them to hunt for fish even in murky waters" — echolocation therefore does both the jobs the statement names, orientation and prey capture. The behaviour matches the anatomy: the animal habitually swims on one side with a flipper trailing the muddy bottom, sweeping the bed for prey it will never see. Statement 4: "Indian ministry of environment and forests declared Ganges river dolphin as National aquatic animal in 2009" — the decision was taken at the first meeting of the National Ganga River Basin Authority, chaired by the Prime Minister, on 5 October 2009, with formal notification following in May 2010. That same date was later adopted as National Dolphin Day, announced on 25 March 2022 after the 67th meeting of the Standing Committee of the National Board for Wild Life and first observed on 5 October 2022, a year before this paper. Nothing in the set is false, so (d) is the answer.

Why the other options are wrong — (a) Drops statement 3, the echolocation claim — but that is the single best-attested fact about the animal, and the option is self-defeating because it keeps statement 2. WII describes a "highly developed bio sonar system" and says the dolphins hunt by emitting ultrasonic sound waves that bounce off prey. A candidate who accepts that the dolphin is blind but doubts that sound alone can steer it has not joined the two halves of one adaptation: a blind predator in a turbid river either has a non-visual sense or it starves. Note too that the statement claims echolocation for navigation as well as hunting, and WII's wording covers both — orientation in murky water is the same acoustic problem as finding a fish in it.  (b) Drops statement 1, the IUCN category. This is usually not ignorance but over-correction: candidates who know the species is rare — WII puts the population below 2,000 — assume the Red List must have it as Critically Endangered and reject the milder-sounding 'endangered'. The formal 2022 assessment of Platanista gangetica (e.T41756A50383346) is Endangered, and WII repeats that classification, so statement 1 stands exactly as written. Rarity and Red List category are not the same measurement: the category is set by quantified criteria on population size, decline rate and range, not by how scarce a species feels, which is why a Schedule I animal on CITES Appendix I can still be assessed one rung below the top.  (c) Drops statement 2, the blindness claim, presumably because 'does not have a crystalline eye lens' reads like an over-specific piece of anatomy that an exam paper is unlikely to have got right. The functional core of it is government-sourced: WII's own description of the species is that they are "essentially blind", and WWF-India's says "generally blind". The lensless eye is the standard scientific explanation for that blindness rather than an official form of words, but nothing in the statement contradicts what WII prints, and the tiny eye plainly lacks the image-forming optics other cetaceans carry — which is exactly why the ultrasonic sense in statement 3 had to evolve so far. Rejecting statement 2 while accepting statement 3, as this option does, leaves you with a sighted animal that navigates by sonar for no reason.

Concept: The Ganges river dolphin, Platanista gangetica gangetica, locally the susu, is one of only five river dolphin species in the world and an obligate freshwater cetacean — it cannot survive in the sea. WII records its range across the Ganga and Brahmaputra basins of India, Nepal and Bangladesh. Living in water too turbid for sight, it has traded eyes for sound: a slit-like blowhole on the crown of the head working as a nostril, a long tooth-lined snout, and an acoustic sense refined enough to find fish it will never see. It surfaces every 30 to 120 seconds to breathe, and the puffing sound of that breath gives it its Hindi name. Females are larger than males and a female produces one calf every two to three years, a reproductive rate so slow that a population knocked down does not bounce back inside a policy cycle. India protects it at the highest level available — Schedule I of the Wild Life (Protection) Act, 1972 — and it is on Appendix I of CITES and Appendix II of the Convention on Migratory Species; WII puts the surviving population below 2,000 individuals. Because it needs deep, continuously flowing water, it is a flagship for the health of the whole river: barrages, sand mining and net entanglement hurt it before they visibly hurt anything else. That flagship status is what has given it a policy apparatus of its own — the Vikramshila Gangetic Dolphin Sanctuary on the Bhagalpur reach of the Ganga since 1991, the National Aquatic Animal designation of 2009, Project Dolphin announced on 15 August 2020, and National Dolphin Day on 5 October since 2022.

State PCS 2023 Q87 — Environment & Ecology PYQ with Answer

State PCS 2023 Q87 — Environment & Ecology PYQ with Answer