UPSC CSE Prelims 2026: With the UPSC Civil Services Preliminary Examination 2026 scheduled for May 24 and only a few weeks remaining, aspirants have now entered the crucial phase of smart revision and selective consolidation. We are sure you already understand the importance of species — both flora and fauna — in the UPSC Prelims examination. At this stage, the focus should not just be on reading new material but also on ensuring that all important biodiversity-related topics from current affairs are properly covered in your revision notes. This becomes even more important because, in recent years, UPSC has increasingly linked biodiversity with current affairs while framing environment questions. For Prelims 2026, aspirants should therefore pay special attention to species that remained in the news due to conservation concerns, ecological significance, invasive behaviour, rediscovery, habitat protection, climate change, or scientific research.

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Other Revision Checklists: Top 30 Environment topics | Top 20 Reports and Indices | Top 25 places in News | Top 30 Geography topics

#1. Cocaine hippos

— The ‘cocaine hippos’ are thriving in the fertile region between Medellín and Bogotá, and are now spreading in the Magdalena River, one of Colombia’s main waterways.

— A reason for their growing numbers is that unlike in Africa, the hippos have no natural predators in Colombia. Being non-native in Colombia, the hippos are considered an invasive species, and their growing population is believed to be a ticking time bomb that will seriously harm indigenous flora and fauna.

— They are considered to be a threat to local species such as the West Indian manatee, Neotropical otter, spectacled caiman, turtles as well as endangered ones such as Dahl’s toad-headed turtle and the Magdalena River turtle. Growth in the number of feral hippos is also expected to cause deadly encounters with humans.

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#2. Peacock Tarantula

— Found predominantly in the deciduous forests of central and southern India, this spider species has a distinct blue hue, one that darkens with age and maturity. The Peacock Tarantula (Poecilotheria metallica) plays a vital role, similar to most species of tarantula, in its ecosystem as a predator that helps maintain the balance of insect populations.

(Source: X/@APDeputyCMO) (Source: X/@APDeputyCMO)

— It is endemic to the Eastern Ghats of India. The species is currently critically endangered, fighting against “habitat loss, degradation and rampant, illegal pet trade for exotic species”.

#3. Bat species in India

— The bat species in India, around 135, are facing neglect due to lack of research and are also under threat from urbanisation, deforestation, land-use changes and climate impacts, the first-ever national assessment (State of India’s Bats, 2024-25) has reported. They play a crucial role in pollinating plants, disperse fruit seeds, control pests that damage crops, and provide soil nutrition through their droppings.

— The report documented significant inter-variability in the distribution of bat species. West Bengal leads with 68 bat species, followed by 66 in Meghalaya, 52 in Uttarakhand 41 each in Kerala and Karnataka and 43 in Sikkim, denoting diversity. Among cities, Delhi had 15 bat species, despite pressures of urbanisation. Haryana, Punjab had only five recorded species with limited forest cover and farm expansion.

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#4. Kakapo

— Native to New Zealand, the kakapo is the world’s only flightless parrot and also the heaviest parrot species on Earth. Adults can weigh up to four kilograms, giving them a round, fluffy appearance that has earned them affectionate nicknames like “moss chicken.”

(Image: WIkimedia commons) (Image: WIkimedia commons)

— Unlike most parrots, kakapo are nocturnal. During the day, they hide in dense forests and come out at night to feed on leaves, fruit, seeds, and bark.

#5. Cycads

— These ancient plants can raise their own temperature. As these plants heat themselves up, an invisible signal is released that helps insects find them in the dark.

(photo credit: Michael Calonje) (photo credit: Michael Calonje)

— Cycads have existed on Earth since the time of dinosaurs and are often described as “living fossils. Unlike modern flowering plants that depend on bees or butterflies, cycads are mainly pollinated by beetles.

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#6. Seagrass

— Seagrasses are marine flowering plants that are found in shallow waters in many parts of the world, from the tropics to the Arctic circle. They form extensive underwater meadows, creating complex, highly productive and biologically rich habitats.

— In May 2022, the General Assembly adopted 1st March as World Seagrass Day.

— These seagrass meadows provide food and shelter to thousands of species of fish, seahorses, turtles, etc. and sustain some of the world’s largest fisheries. They improve water quality by filtering, cycling and storing nutrients and pollutants, reducing contamination in seafood. They act as the first line of defense along coasts by reducing wave energy, protecting people from the increasing risk of floods and storms.

— It is highly protected under Schedule I of the Indian Wildlife (Protection) Act of 1972.

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— It is primarily a riverine turtle, inhabiting small and large rivers.

— It is included in CITES Appendix II, which allows for international commercial traffic in the species as long as it is not harmful to the species and complies with national trade legislation.

— Adult females are primarily herbivorous, whereas males and juveniles are more carnivorous. The Indian tent turtle (Pangshura tentoria) is rated as Least Concern (LC) on the IUCN Red List of Threatened Species.

#8. Bactrian camels

— At the annual Republic Day parades, the Indian Army’s Remount and Veterinary Corps (RVC) are generally represented by the dog squad. This year, in a first time, other animals will also be part of the parade.

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— Adapted to extreme cold and altitudes above 15,000 feet, Bactrian camels can carry loads of up to 250 kilograms and negotiate steep gradients and sandy terrain, supporting logistics and mounted patrolling along the Line of Actual Control (LAC).

The camels during a rehearsal for the parade. (Special arrangement) The camels during a rehearsal for the parade. (Special arrangement)

— These ponies carry loads of 40 to 60 kilograms over long distances and are employed for logistics and patrol duties in high Himalayan regions, including Siachen.

— The double-humped camel, or Bactrian camel, is found exclusively in the high-altitude cold desert of Ladakh. Bactrian camels are native to Central Asia, such as Mongolia, China, Kazakhstan, etc.

Camels in India Camels are well suited to their desert habitats, with numerous clever physiological adaptations helping them tolerate extreme hot (and cold) environments. India is home to several camel breeds, including Bikaneri, Jaisalmeri and Mewari in Rajasthan’s Thar Desert, and Kachchhi and Kharai in the Rann of Kutch in Gujarat. Ladakh’s inhospitable high-altitude cold desert climes also support two-humped Bactrian camels.

#9. Octopuses

— Octopuses are cold-blooded animals, and they are known to thrive in warm waters. A 2023 study, published in the journal Science Advances, showed that higher temperatures increase the rate of embryonic development in the animal. It found that at 11 degrees Celsius, octopus eggs hatched in less than two years. On the other hand, eggs of the deep-sea octopuses, which live at roughly 1.6 degrees Celsius, took four-and-a-half years to hatch.

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— Octopus is a voracious predator, as it requires three times its weight to sustain itself. This means that a sustained high number of octopuses could impact the population of their favourite prey, such as crabs, scallops, and lobsters.

— Warmer waters help octopuses proliferate, extreme temperatures are detrimental to them. About 70% of the octopus’s brain is dedicated to vision, and it plays a crucial role in communication and detecting predators and prey.

— Octopuses usually crawl along the seafloor instead of swimming long distances. Octopus blood is blue instead of red, which makes them even stranger. Their blood is blue because it contains hemocyanin, a copper-based molecule that carries oxygen, rather than the iron-based hemoglobin found in humans.

#10. White-bellied heron

— The white-bellied heron, a schedule-I (highest protection) species under the Wildlife Protection Act.

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— The bird is critically endangered, as per the red list of the International Union on Conservation of Nature (IUCN). The bird’s presence has been recorded both, upstream and downstream, of the Kalai-II project, as per independent researchers, and past records of the Arunachal Forest Department.

— In India, the species is currently confined to Arunachal Pradesh. Their population is found in Lohit, Anjaw, and Changlang districts, including in Kamlang and Namdapha tiger reserves. The IUCN Red list suggests there are less than 250 birds in the wild; experts speculate there might be only about 60 birds left in the wild, with 4-5 breeding pairs in Bhutan and fewer in eastern Arunachal Pradesh.

#11. Galaxy frogs

— Galaxy frogs (Melanobatrachus indicus) are one of the rarest and most dazzling amphibians in the world that live exclusively under rotten logs in Kerala’s Western Ghats. However, the elusive species is now disappearing.

— The frogs are listed as vulnerable to extinction by the International Union for Conservation of Nature.

(Photo: Wikimedia Commons) (Photo: Wikimedia Commons)

— Among major threats to these creatures are the conversion of forest areas to farm land, firewood collection and landslides. However, in recent years, photo tourism has emerged as a new danger to galaxy frogs, especially after they were designated as the flagship species of Kerala’s Mathikettan Shola National Park in 2021.

#12. Rheum nobile

— This plant, which thrives at elevations ranging from 4,000 to 4,800 meters, is part of a remarkable species known as “glasshouse plants.” Its long, translucent bracts function as natural greenhouses, trapping heat and shielding the delicate blooms inside from chilling winds and harsh UV rays. Against the austere Himalayan scenery, the plant appears almost incandescent, like a shimmering tower rising from the rock and snow.

Sikkim Sundari (Photo: Wikipedia) Sikkim Sundari (Photo: Wikipedia)

— This plant is monocarpic, so it flowers just once in its life. For 7 to 30 years, it stays close to the ground as a small rosette of leaves, quietly saving energy in tough mountain conditions.

— The Sikkim Sundari is both a privilege and a poignant reminder of the fragility of Himalayan ecosystems. It is typically found along high-altitude trekking routes in North Sikkim, particularly near alpine passes and glacial valleys. Because it grows in such extreme environments, sightings are rare and seasonal, making the experience even more special for nature lovers and photographers.

#13. Vulture in India

— India has nine species of vultures in the wild. These are the Oriental White-backed Vulture (Gyps bengalensis), Slender billed Vulture (Gyps tenuirostris), Long billed Vulture (Gyps indicus), Egyptian Vulture (Neophron percnopterus), Red Headed Vulture (Sarcogyps calvus), Indian Griffon Vulture (Gyps fulvus), Himalayan Griffon (Gyps himalayensis), Cinereous Vulture (Aegypius monachus) and Bearded Vulture or Lammergeier (Gypaetus barbatus).

— The population of three species i.e. White-backed Vulture, Slender billed Vulture and Long billed Vulture in the wild has declined drastically over the past decade. All three vulture species were listed by IUCN, the World Conservation Union, in 2000 as ‘Critically Endangered’. Not all vulture species are classified as critically endangered.

— The decline in vulture populations, primarily due to the use of veterinary drugs like Diclofenac, was catastrophic. While the drug was banned in 2006, its effects still linger.

#14. Jellyfish

— The largest nuclear power plant in France was forced to temporarily shut down due to a slimy and spineless adversary: jellyfish.

— Nuclear power plants require a constant flow of water to cool their reactors and turbine systems, which is why many plants are typically built near large bodies of water. The plants’ intake pipes have screening areas that have grated barrier systems to remove solid materials and aquatic life, and allow the inflow of water, sometimes millions of gallons every minute.

— However, jellyfish pose a unique problem to this system. When a large volume of jellyfish — around a million individuals — gets pulled in by the intake pipes, they entirely cover and clog the screening areas within minutes. As a result, the flow of water is interrupted. This risks overheating and damage to the major plant constituents, such as the turbines, condensers, and boilers, forcing the reactors to shut down.

Several factors are contributing to the proliferation of jellyfish: Climate Change: Global warming has caused higher ocean temperatures, resulting in an increase in plankton, jellyfish’s principal food supply. Jellyfish populations have grown significantly due to the availability of food available. Overfishing: It has also led to an increase in jellyfish populations. This is because other animals that prey on them, such as tuna and sea turtles, have been eliminated from the environment. These species also feed on plankton, and with a smaller population, jellyfish have more plankton to ingest and thrive uncontrolled. Plastic Pollution: Unlike other marine creatures, jellyfish can tolerate low oxygen levels in water, which is a consequence of pollution. This has also contributed to the increase in their population in recent years.

#15. Sea cows

— In the South Asian region, dugongs, also known as sea cows, are primarily found in the Gulf of Kutch, the Gulf of Mannar–Palk Bay region (located between India and Sri Lanka), and the Andaman and Nicobar Islands.

— Currently, the IUCN, which compiles the official Red List of endangered species, lists sea cows as a species vulnerable. In India, they are listed under Schedule I of the Wild Life (Protection) Act, 1972, which grants the species the highest legal protection against hunting and trade.

— Dugongs (Dugong dugon) are a marine mammal, which are believed to have inspired ancient seafaring tales of mermaids due to their gentle — seemingly benign — disposition. They are related to manatees, with whom they share a plump appearance, but also have a dolphin fluke-like tail. An adult dugong typically grows up to 10 feet and weighs around 420 kilograms. The mammals are exclusively herbivorous, and seagrass meadows are their main source of food — the reason why they are also called sea cows.

#16. Ghariyal and Crocodile

— Ghariyal and Crocodile are in Schedule-I of the Wildlife (Protection) Act, 1972, thereby affording them the highest degree of protection.

— The National Chambal Gharial Sanctuary, which houses over 80% of India’s gharial population while the Bhitarkanika (Odisha) is famous for saltwater crocodiles.

#17. Asian elephant

— According to the Synchronous All India Elephant Estimation (SAIEE) 2021-25, 2,446 elephants have been reported in the country, primarily concentrated across the Western Ghats in the southern states, and the hills and plains of the Northeast.

— The Asian elephant (Elephas maximus) is an endangered species. It has been on the IUCN Red List, which details the global conservation status of animal, fungi and plant species, since 1986.

— Compared to the last all-India estimate in 2017 (27,312), the population is lower by 4,065 elephants, or 17.81%. However, the population report added a caveat that the two figures are not directly comparable due to a change in methodology, and said the latest estimate should be treated as a “new baseline.”

— As per official data, India accounts for the largest population, over 60%, of the endangered species. The largest mammal found in India’s forests, elephants have been counted every five years since the launch of Project Elephant in 1992. According to the report, Central India & Eastern Ghats boast 1,891 elephants with Uttarakhand (1,792), Uttar Pradesh (257) and Bihar (13).

— As per the latest data, elephant numbers remain highest in the Western Ghats (11,934), followed by the North Eastern Hills and Brahmaputra floodplains (6,559), Shivalik Hills and Gangetic plains (2,062), and Central India and Eastern Ghats (1,891).

— Among states, Karnataka continues to harbour the largest population (6,013), followed by Assam (4,159), Tamil Nadu (3,136), Kerala (2,785), Uttarakhand (1,792), and Odisha (912).

#18. Ghost flowers

— Ghost flowers are some of nature’s most hauntingly beautiful plants, known for their ghostly pale white appearance and their unique ability to survive without sunlight or photosynthesis. These botanical ‘spectres’ pop up in shaded forests.

— Ghost flower is the common name for ‘Monotropa uniflora’, also called ‘ghost plant’, ‘Indian pipe plant’, ‘corpse plant’, or ‘ice plant’. Unlike typical green plants, ghost flowers are almost always pure white or pinkish white due to the absence of chlorophyll — the pigment used by plants for photosynthesis. For some lucky observers, rare red varieties may be spotted too.

— Ghost flowers rely on a completely different tactic — hijacking underground fungi for sustenance. These fungi are connected to tree roots and help exchange nutrients. Bumblebees are the main pollinators of ghost flowers.

#19. Great Indian Bustard

— GIBs are a critically endangered species. It is recognised as a vital indicator species of the grassland habitat, which means that its survival indicates the health of grassland ecosystems.

— According to the Rajasthan Forest Department, its population has steadily fallen over the last four decades, from over 700 individuals to less than 150 presently.

#20. Morels (Morchella)

— Morels or Morchella, locally known as Kangaech, that grows naturally in specific high elevation forest ecosystems during a narrow rainy season costs anything between Rs 15,000 to Rs 40,000 per kilogram.

— Morchella is a highly valued gourmet mushroom known for its intense and distinct flavour, superior nutritional profile and medicinal properties. The harvesting of the wild Morchella is a laborious and time-consuming process as gatherers carefully scour dense forests in harsh weather conditions. Sometimes, they return empty handed even after several days of foraging.

— The cultivation of Morchella has been a major scientific challenge especially as the species is known for a complex life cycle, symbiotic ecological behaviour and highly specific environmental requirements that makes the artificial cultivation extremely difficult.

— The cultivation of Morchella under controlled conditions is likely to open new frontiers in the high value bioeconomy of Jammu and Kashmir.

#21. Gangetic dolphins

— The Gangetic dolphins, India’s national aquatic animal, are found largely in the Ganges-Brahmaputra river system in the northern part of the country.

— They have also been classified as “endangered” by the International Union for Conservation of Nature (IUCN). These species can be found swimming in the Ganges, Brahmaputra, Karnaphuli, and Meghna rivers and their tributaries in India, Bangladesh, Nepal, and Bhutan. The adult can go up to 10 feet long, swimming on its side and leaving a flipper trailing behind to hunt for fish, shrimp and molluscs.

FYI: The Amazon river dolphin, also known as the ‘pink river dolphin or boto’, is a freshwater species that inhabits water bodies in the Amazon and Orinoco river basins in Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, and Venezuela.

#22. Polar bears

— Polar Bears have black skin. Their fur is hollow and transparent, with no white pigment coating the shaft. However, they have a double coat of fur for protection, along with a thick layer of body fat. The external layer of fur, made of keratin, has light-reflecting properties.

— When the sun hits a polar bear‘s fur, light rays are trapped inside, creating a luminescent effect that gives it an off-white shade. The colour helps polar bears camouflage with the Arctic surroundings and icy environment. A carnivorous member of the bear family, Polar bears feed on fatty seals for fat and energy to survive in harsh weather conditions. Their stomachs have a large food storage capacity and high protein and fat absorption.

— Polar bears are skilled swimmers, moving through water at speeds up to six miles an hour. They are often considered marine mammals because of their time spent on sea ice, waddling through the icy waters of the Arctic with their webbed front paws and hind legs.

🚨 Click Here to read the UPSC Essentials magazine for May 2026. Share your views and suggestions in the comment box or at manas.srivastava@indianexpress.com🚨

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