Reptilia · Squamata
Hydrophis schistosusDaudin, 1803
Hook-nosed sea snake
Photograph by Shaunak Modi, CC BY, via iNaturalist
An active by day or night, meat-eating snake from the Oriental region, reaching 189 cm nose to tail.
Also called Common or beaked seasnake.
Once published as Enhydrina schistosa — those names reach this page.
Reptilia › Squamata › Elapidae › Hydrophis
- Grows to
- 1893mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives
- Marine
Longer than 89% of all elapid snakes anyone has measured.
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 219 to 5,710 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
39 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
- Still living
- Extant
- Conservation status
- Least Concern
- Status assessed · the year the Red List last looked
- 2009
- Population trend
- Stable
The animal itself
- Limbs
- None
- Venomous
- Yes
- Fangs
- At the front of the mouth
Size
- Length snout to vent · greatest recorded
- 1774mm5 ft 10 in
- Length snout to vent · adult female mean
- 1032mm3 ft 5 in
- Length nose to tail · greatest recorded
- 1893mm6 ft 3 in
- Female length · mean, nose to tail
- 1107.9mm3 ft 8 in
- Hatchling length · snout to vent
- 225mm8.75 in
- Body mass · greatestcomputed
- 1195.9g2.6 lb
- Body mass · adult female, meanmeasured
- 532g1.2 lb
- Body mass at hatchingmeasured
- 11.4g0.4 oz
1200 mm total length (Feldman et al. 2016), max 130 cm total length (Kamali 2020), max 1230 mm (Carranza et al. 2021), Voris and Jayne 1979 (largest embryo 233 mm, "birth. Data in Table 2 suggest that the s-v length at birth could be expected to range from about 21 to 24 cm" females 73-112 cm, mean 925 mm SVL), Ukuwela et al. 2022 (gravid females 621 and 1293 mm, mean=1054.88 mm, SD=±238.81 mm), Dsouza and Rao 2021: largest female was 183 cm long; de Silva et al. 2011 (total lengths of 6 gravid females 1011–1893, mean 1161 mm, SVLs 890-1774, mean 1138), Lemen and Voris 1981 (39 females 536.1 g; neonates 11.4 g)
snakes only in this source
computed from length by a family-level allometric equation, not weighed
How it lives
- Diet
- Carnivorous
- How it hunts
- Active foraging
- Active
- Cathemeral
- Where it lives
- Marine
- Habitat
- Wetlands
- Biome
- Mangroves
- Active season · months of the year
- 12months
- Region
- Oriental
- Mainland or island
- Marine
- Range size
- 80km²
fish (Kamali 2020, Carranza et al. 2021, Ukuwela et al. 2022)
Banfi et al. 2023
O'Shea 1996, Kamali 2020
Aquatic (O'Shea 1996)
Breeding
- Reproduction
- Viviparous
- Sex decided by
- Genes, ZW/ZZ
- Average clutch
- 7.75eggs
- Eggs or young per clutch
- 4–34eggs
- Mean clutch
- 12.7–18.7eggs
- Clutches a year
- 1per year
- First breeds at
- 18months
O'Shea 2011
4-34 (O'Shea 2011), 4-33 (Whitaker and Captain 2004), 4-11 (Carranza et al. 2021), Voris and Jayne 1979 (18.7 if I combine data fpr the left and right ovaries, looks like the range is 3-33 in Fig. 3), 7-16, mean 12.7 (Ukuwela et al. 2022), 7-16 (de Silva et al. 2011), Bergman 1943 (2 females 11 eggs), Lemen and Voris 1981 (9-34, Figure 2)
Naming and history
- Suborder
- Serpentes
- Infraorder
- Alethinophidia
- Subspecies
- No
- Described by
- Daudin
- Moved to another genus · since it was first described
- No
- Described in
- 1803
- Type locality
- Bangladesh
Keeping one
6 ft 3 in × 3 ft 1 in × 4 ft 8 in(189 × 95 × 142 cm)
Minimum length × width × height, for one animal. Bigger is always better.
The standard sizes snakes as a fraction of total length: 1 × 0.5 × 0.75.
Mindestanforderungen an die Haltung von Reptilien (Sachverständigengutachten), German Federal Ministry for Nutrition, Agriculture and Forestry, Animal Welfare Division, 10 January 1997. The standard states these floor areas are recommendations rather than binding limits.
From this animal’s own total length of 6 ft 3 in (1893 mm), at 1 × 0.5 × 0.75 times it, following the German federal welfare standard — how this is worked out.
No preferred body temperature has been recorded for Hook-nosed sea snake. Rather than repeat a number from a care sheet, this page leaves it out.
Feeding
A prey item should be between the same width as the widest part of the snake's body and about 1.5 times that width.
Widely used across snake husbandry references. An alternative formulation gives prey at 10-15% of the snake's body mass. This is established practice, not a measurement.
107kJ per day
Worked out for an animal of 1,196 g, the heaviest recorded for Hook-nosed sea snake — 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.
- — Length snout to vent · adult male mean
- — Length snout to vent · adult mean
- — Length nose to tail · adult male mean
- — Length nose to tail · adult mean
- — Largest female · snout to vent
- — Largest male · snout to vent
- — Largest female · shell length
- — Largest male · shell length
- — Hatchling length · nose to tail
- — Largest juvenile · snout to vent
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · a typical adult
- — Longest recorded life
- — Preferred body temperature · chosen in a laboratory gradient
- — Body temperature when active · measured in the wild
- — Eats arthropods
- — Eats vertebrates
- — Eats plant matter
- — How the young develop
- — Gestation or incubation
- — Clutches in a year
- — 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
- — Colour on the back
- — Pattern on the back
- — Pupil
- — Red List criteria
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Active in
- — Lowest it lives · above sea level
- — Highest it lives · above sea level
Others in Elapidae
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). Hydrophis schistosus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/hydrophis-schistosus
@misc{hydrophis_schistosus_2026,
title = {Hydrophis schistosus},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/hydrophis-schistosus}
}Sources
- Meiri, S. (2024). SquamBase — a database of squamate (Reptilia: Squamata) traits. Global Ecology and Biogeography. Public domain (CC0).
- Oskyrko, O. et al. (2024). ReptTraits: a comprehensive dataset of ecological traits in reptiles. Scientific Data. Used under CC BY 4.0.
- Catalogue of Life (dataset 3LR), used under CC BY.