Reptilia · Squamata
Eryx jaculusLinnaeus, 1758
Javelin Sand Boa
Photograph by Guy Haimovitch, CC BY-SA, via Wikimedia Commons
A burrowing, active by day or night, meat-eating snake from the Saharo-Sindian region, reaching 838 mm nose to tail.
Reptilia › Squamata › Boidae › Eryx
- Grows to
- 838mm
- greatest recorded
- Eats
- Carnivorous
- Active
- Cathemeral
- Lives up to
- 24.7years
Longer than only 17% of all boas 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 109 to 6,700 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
40 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
- 2016
- Population trend
- Decreasing
The animal itself
- Limbs
- None
- Pupil
- Vertical slit
- Venomous
- No
- Fangs
- None
- Longest recorded life
- 24.7years
Stark et al. 2020 (24.7), estimates 20-25 (Albarwari 2021)
Size
- Length snout to vent · greatest recorded
- 738mm2 ft 5 in
- Length snout to vent · adult female mean
- 578mm23 in
- Length nose to tail · greatest recorded
- 838mm2 ft 9 in
- Hatchling length · snout to vent
- 160mm6.25 in
- Hatchling length · nose to tail
- 115mm4.5 in
- Body mass · greatestcomputed
- 289.6g10.2 oz
- Body mass · a typical adult
- 196g6.9 oz
- Body mass · adult female, meanmeasured
- 148.3g5.2 oz
- Body mass at hatchingmeasured
- 2g0.07 oz
800 mm total length (Feldman et al. 2016), 838 from Egypt (Naumov et al. 2020, 84 cm in Trape 2023), 900 mm max total length (Kamali 2020: too long?), Steinhardt collections: max 795 mm total length, 738 mm max SVL, Bar et al. 2021 (135-800 mm total length, 2-350 g), 345 g (the Steinhardt Museum of Natural History, mean fmale SVL 577.8, n = 17, Aug2023, mean neonate SVL 160 mm), max 84-87 cm (Dunayev and Orlova 2023), Aidek et al. 2023 (max 60 cm), Spawls et al. 2023 (30 to about 90 cm, hatchlings 90-14 cm)
snakes only in this source
computed from length by a family-level allometric equation, not weighed
AnAge rates this record "acceptable"
How it lives
- Diet
- Carnivorous
- How it hunts
- Sit and wait
- Active
- Cathemeral
- Where it lives
- Fossorial
- Habitat
- Desert, Grassland, Shrubland
- Biome
- Mediterranean
- Active season · months of the year
- 6months
- Region
- Saharo-Sindian
- Mainland or island
- Mainland
- Highest it lives · above sea level
- 1700m
- Range size
- 2,585,451km²
insects, birds, lizards and rodents (Kamali 2020), mostly mammals, then lizard eggs, then lizards (71.4%, 30.2% and 7.9%, respectively, who?), lizards and rodents mainly, also birds, snakes and their eggs, and large insects (Dunayev and Orlova 2023, see also Spawls et al. 2023)
Sit (O'Shea 2018)
Nocturnal (O'Shea 2018, Shai Meiri, personal observations, Eid 2021, Spawls et al. 2023), diurnal (Kamali 2020; doubtful), Nocturnal and crepuscular (Bar et al. 2021), nocturnal and crepiuscular in summer, diurnal in spring and autumn (Dunayev and Orlova 2023)
"fossorial (leaf litter, termite mounds), > 50% digging" (Gearty et al. 2021), fossorial (Spawls et al. 2023), I also saw it in the open and even on a rock wall in Greece
0-1500 (O'Shea 2018), 30-1080 (Shai Meiri, pers. observations), max 1700 (Dunayev and Orlova 2023), max 1600 (Spawls et al. 2023)
Breeding
- Reproduction
- Viviparous
- Average clutch
- 13eggs
- Eggs or young per clutch
- 1–20eggs
- First breeds at
- 36months
(Feldman et al., 2015), ovoviviparous (del Marmol et al. 2019, Geniez 2018, Spawls et al. 2023)
1-20 (Chippaux and Jackson 2019, Dunayev and Orlova 2023), 3-20 (del Marmol et al. 2019), 6-20 (O'Shea 2018), 20 (Eid 2021), 3-12 (Spawls et al. 2023)
Naming and history
- Suborder
- Serpentes
- Infraorder
- Alethinophidia
- Subspecies
- No
- Described by
- Linnaeus
- Moved to another genus · since it was first described
- Yes
- Described in
- 1758
- Type locality
- Egypt
Keeping one
2 ft 9 in × 16.5 in × 2 ft 1 in(84 × 42 × 63 cm)
Minimum length × width × height, for one animal. Bigger is always better. Substrate at least 16.5 in (42 cm) deep.
The standard sizes snakes as a fraction of total length: 1 × 0.5 × 0.75.
Burrows, so substrate deep enough to dig in matters as much as floor area.
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 2 ft 9 in (838 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 Javelin Sand Boa. 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.
30kJ per day
Worked out for an animal of 290 g, the heaviest recorded for Javelin Sand Boa — 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
- — Female length · mean, nose to tail
- — 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
- — 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
- — Mean clutch · smallest reported
- — Mean clutch · largest reported
- — Clutches in a year
- — Clutches a year · fewest
- — Clutches a year · most
- — 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
- — Sex decided by
- — Red List criteria
- — Density · lowest recorded
- — Density · highest recorded
- — Home range · largest recorded
- — Active in
- — Lowest it lives · above sea level
Others in Boidae
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). Eryx jaculus. Retrieved 2026-09-08, from https://www.allanglescreatures.com/species/eryx-jaculus
@misc{eryx_jaculus_2026,
title = {Eryx jaculus},
author = {{The Reptile & Amphibian Encyclopedia}},
year = {2026},
url = {https://www.allanglescreatures.com/species/eryx-jaculus}
}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.
- AnAge, Human Ageing Genomic Resources (de Magalhães et al.), used under CC BY 3.0.