Reptilia · Squamata
Hydrophis cyanocinctusDaudin, 1803
Annulated Sea Snake
Photograph placed in the public domain, CC0, via iNaturalist
An active by day or night, meat-eating snake from the Marine region, reaching 193 cm nose to tail.
Also called Dusky-chinned giant sea snake.
Reptilia › Squamata › Elapidae › Hydrophis
- Grows to
- 1931mm
- 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
33 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
The animal itself
- Limbs
- None
- Colour on the back
- Brown, Gray, Yellow
- Venomous
- Yes
- Fangs
- At the front of the mouth
Size
- Length snout to vent · greatest recorded
- 1181mm3 ft 10 in
- Length nose to tail · greatest recorded
- 1931mm6 ft 4 in
- Female length · mean, nose to tail
- 1109.9mm3 ft 8 in
- Hatchling length · snout to vent
- 370mm14.5 in
- Hatchling length · nose to tail
- 420mm16.5 in
- Body mass · greatestcomputed
- 440.8g15.5 oz
- Body mass at hatchingmeasured
- 18g0.63 oz
2750 mm total length (Feldman et al. 2016), max 172 cm (Kamali 2020), 1447 mm (Carranza et al. 2021), Wang et al. 2023 (female standard length [probably TL, unsure] 935~1931 mm), Karthikeyan and Balasubramanian 2008 (newborn males Weight (g) 17 ±1 females 19 ± 1 g, Total length (cm) males: 38 ± 0.5, females: 46 ± 1, Snout vent length (cm) males: 33 ±1 females: 41 ± 1), Ukuwela et al. 2022 (Females in reproductive condition 757-1295 mm (mean=1109.91 mm, SD=±167.29 mm), de Silva et al. 2011 (1 female 1181 mm SVL, 1285 mm total length, gravid, reproductive females 965-1285 mm TL)
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
- Marine Neritic
- Region
- Marine
- Mainland or island
- Marine
fish (Kamali 2020, Carranza et al. 2021, Karthikeyan and Balasubramanian 2008, Ukuwela et al. 2022)
Wang et al. 2023
Kamali 2020
Breeding
- Reproduction
- Viviparous
- Sex decided by
- Genes, ZW/ZZ
- Average clutch
- 8eggs
- Eggs or young per clutch
- 3–16eggs
- Mean clutch
- 4.14eggs
Whitaker and Captain 2004
3-16 (Whitaker and Captain 2004, Carranza et al. 2021), 3-5 (Karthikeyan and Balasubramanian 2008, n = 87, Among 25 gravid snakes maintained, 21 released a total of 87 young), de Silva et al. 2011 (5, n = 1), Bergman 1943 (21 uterine eggs in 2 females)
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
- Oman
Keeping one
6 ft 4 in × 3 ft 2 in × 4 ft 9 in(193 × 97 × 145 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 4 in (1931 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 Annulated 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.
44kJ per day
Worked out for an animal of 441 g, the heaviest recorded for Annulated 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.
Other inherited traits
Inherited characteristics and conditions recorded for this species. These are not morphs — nobody breeds for them.
- Adaptation, environment1 reference
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 female mean
- — 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
- — Largest juvenile · snout to vent
- — Largest juvenile · shell length
- — Egg length
- — Egg width
- — Body mass · a typical adult
- — Body mass · adult female, mean
- — 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
- — 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
- — Pattern on the back
- — Pupil
- — Population trend
- — Red List criteria
- — Biome
- — Active season · shortest recorded
- — Active season · longest recorded
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Active in
- — Lowest it lives · above sea level
- — Highest it lives · above sea level
- — Range size
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 cyanocinctus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/hydrophis-cyanocinctus
@misc{hydrophis_cyanocinctus_2026,
title = {Hydrophis cyanocinctus},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/hydrophis-cyanocinctus}
}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.