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Testudines · TrionychidaeEntry 13,730 of 21,572
Burmese Soft-shelled Turtle, Nilssonia formosa

Reptilia · Testudines

Nilssonia formosaGray, 1869

Burmese Soft-shelled Turtle

Photograph placed in the public domain, CC0, via iNaturalist

A nocturnal turtle from the Oriental region, reaching 650 mm nose to tail.

Reptilia › Testudines › Trionychidae › Nilssonia

Grows to
650mm
greatest recorded
Active
Nocturnal
Lives
Aquatic, terrestrial
Weighs up to
22,187g
greatest
Body length across Trionychidae

Longer than 54% of all species in Trionychidae anyone has measured.

54% of 28 species are smaller46% larger
230 mmthe whole family, smallest to largest2,000 mm

The bar is the rank itself: its length is the share of the family this animal exceeds. The chart below is the family’s real spread, on a logarithmic scale because body length here runs from 230 to 2,000 mm. The solid rule is this animal. Every bar is a count of real species, and nothing on this figure is estimated.

What is known

16 sourced facts, each taken from a named scientific dataset. How to read these.

Cited from a dataset unless a row is marked otherwise.

Standing in the world

Conservation status
Critically Endangered
Population trend
Decreasing

The animal itself

Pupil
Round
Venomous
No
Fangs
None

Size

Length nose to tail · greatest recorded
650mm2 ft 2 in

total length, tail included — Colston, Kulkarni, Jetz, and Pyron, 2020, BMC Evol. Biol., 20:81

Body mass · greatestcomputed
22,187g49 lb

largely converted from length by allometry in the source

How it lives

Active
Nocturnal
Where it lives
Aquatic, terrestrial
Habitat
Wetlands
Region
Oriental

Breeding

Reproduction
Oviparous

Naming and history

Subspecies
No
Described by
Gray
Moved to another genus · since it was first described
Yes
Described in
1869

Keeping one

Burmese Soft-shelled Turtle is assessed as Critically Endangered on the IUCN Red List. Species at risk in the wild are often covered by CITES and by national law, which decide what may be bought, sold, moved across a border or kept at all — and captive-bred and wild-caught animals are usually treated differently. Check the rules where you are before acquiring one. Nothing below is a judgement about keeping this species; it is what a published welfare standard says about space, and what the animal itself was measured doing.

No enclosure size is given here

The standard sets enclosure size for turtles and tortoises genus by genus, and this genus is not among the roughly sixty it lists. No figure is given rather than one borrowed from a different animal.

No preferred body temperature has been recorded for Burmese Soft-shelled Turtle. Rather than repeat a number from a care sheet, this page leaves it out.

Feeding

1432kJ per day

Worked out for an animal of 22,187 g, the heaviest recorded for Burmese Soft-shelled Turtle — so it is the top of the range, not a figure for a particular animal. Weigh yours and the number will be lower.

An upper estimate, not a feeding target, and not veterinary advice. The equation covers only what an animal burns staying alive, so a growing, gravid or recovering animal needs more — and it was measured on wild animals, which move far more than one in an enclosure. Body condition and a vet who knows the species are what a feeding decision should rest on. Where this comes from.

What nobody knows

These are not gaps in our research. No scientific dataset records them for this species — and saying so is information you cannot get from a reference that simply leaves a field out.

  • — Still living
  • — Length snout to vent · greatest recorded
  • — Length snout to vent · adult female mean
  • — Length snout to vent · adult male mean
  • — Length snout to vent · adult mean
  • — Female length · mean, nose to tail
  • — Length nose to tail · adult male mean
  • — Length nose to tail · adult mean
  • — Shell length, front to back · greatest recorded
  • — Largest female · snout to vent
  • — Largest male · snout to vent
  • — Largest female · shell length
  • — Largest male · shell length
  • — Hatchling length · snout to vent
  • — Hatchling length · nose to tail
  • — Largest juvenile · snout to vent
  • — Largest juvenile · shell length
  • — Egg length
  • — Egg width
  • — Body mass · a typical adult
  • — Body mass · adult female, mean
  • — Body mass at hatching
  • — Longest recorded life
  • — Preferred body temperature · chosen in a laboratory gradient
  • — Body temperature when active · measured in the wild
  • — Diet
  • — Eats arthropods
  • — Eats vertebrates
  • — Eats plant matter
  • — How it hunts
  • — How the young develop
  • — Gestation or incubation
  • — Average clutch
  • — Smallest clutch recorded
  • — Largest clutch recorded
  • — Mean clutch · smallest reported
  • — Mean clutch · largest reported
  • — Clutches in a year
  • — Clutches a year · fewest
  • — Clutches a year · most
  • — First breeds from · youngest recorded
  • — First breeds by · oldest recorded
  • — Hatchling length · smallest recorded
  • — Hatchling length · largest recorded
  • — Age at first breeding · female
  • — Mature from · youngest recorded
  • — Mature by · oldest recorded
  • — Size at maturity · smallest recorded
  • — Size at maturity · largest recorded
  • — Body temp in the wild · lowest mean recorded
  • — Body temp in the wild · highest mean recorded
  • — Limbs
  • — Colour on the back
  • — Pattern on the back
  • — Sex decided by
  • — Status assessed · the year the Red List last looked
  • — Red List criteria
  • — Biome
  • — Active season · shortest recorded
  • — Active season · longest recorded
  • — Density · lowest recorded
  • — Density · highest recorded
  • — Home range · largest recorded
  • — Suborder
  • — Infraorder
  • — Type locality
  • — Active in
  • — Mainland or island
  • — Lowest it lives · above sea level
  • — Highest it lives · above sea level
  • — Range size

Others in Trionychidae

Take this data

Everything on this page is available as data under CC BY 4.0 — use it freely, credit it, no permission needed.

This species as JSON · the whole dataset

Cite this page

The Reptile & Amphibian Encyclopedia (2026). Nilssonia formosa. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/nilssonia-formosa

@misc{nilssonia_formosa_2026,
  title  = {Nilssonia formosa},
  author = {{The Reptile & Amphibian Encyclopedia}},
  year   = {2026},
  url    = {https://www.allanglescreatures.com/species/nilssonia-formosa}
}

Sources

  1. Moura, M. R. et al. TetrapodTraits: a database of 33,281 tetrapod species. Used under CC BY 4.0. Observed values only; this encyclopedia does not publish its imputed predictions.
  2. Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
  3. Catalogue of Life (dataset 3LR), used under CC BY.