The modest leatherjacket, or leather jacket, is a marine fish with tough skin and a sharp spine instead of the first dorsal fin. It inhabits coastal waters of the northwestern Pacific Ocean and feeds on small bottom-dwelling animals.
The leather jacket differs from related species by its very rough skin and long dorsal spine. It is important for nature because it controls the population of small invertebrates on the seabed.
Immature form that undergoes metamorphosis before adulthood.
Worker
Dorsal spine count
birth time
bottom
Dogs, dolphins, lynx hang out for 9-25 years and party on their birthday three times a year
m
Map
will celebrate their {n} birthday
g
t
When your next jubilee falls in {name} life years
Human
days
worms
marine pelagic
coral and rocky reef
How old you would be if you lived as {name}
Theoretical maximum lifespan estimated from the Dynamic Energy Budget (DEB) mathematical model. This value reflects a biological potential derived from metabolic parameters, not from direct observation — real recorded lifespans are often significantly shorter.
adult
Maturity
fish of small size
crabs
sea urchins and stars
live marine and freshwater shrimps
About health
marine coastal
Pectoral fins count
When your next birthday would fall if you lived as {name}
Repro interval
results
small snails, mussels and other mollusks
Colors
Sex
Upcoming jubilees
Gremllins
mo
all seas and oceans
Trophic type
Filters
small fish
Upcoming birthdays
Truly long lives: 40-100 years. Bowhead whales, albatrosses, giant tortoises recall their birthday at most once a year
Lifespan
Age (juvenile)
Age (from birth to death)
Foraging occurs on the floor of aquatic or terrestrial habitats.
Age (embryo)
most of Europe and Asia, various forests, steppes and tundra
Wanderers
Jubilee = every 10th birthday
Earliest developmental stage inside an egg or womb.
Business sausages
Lifespan average
young after fast growth
Juvenile stage following larval metamorphosis but not yet adult.
What do they look like?
Maturity
emergence (insects)
end of lifespan
live echinoderms, sea stars, urchins, sea cucumbers
How do they live?
fertilization / egg laying
How do they behave?
birth / hatching
metamorphosis / end of larval stage
end of acceleration
the upper illuminated layer of the sea, 0–200 meters
Share
Find a pet...
Mature, fully developed individual capable of reproduction.
Egg count
water is cool or warm, cold in winter, comfortable to swim in summer
Actively hunting and capturing live prey.
Pets
Primary oral structure used to seize, manipulate, or ingest food.
Dorsal spine size
{name} jubilee
cm
Old-timers
Find an animal or breed...
mouth
turns
Rascals
after fast growth and adult
Litter size
live crabs, shrimps, lobsters
Map data sources: Ecosystem classification — IUCN Global Ecosystem Typology (Keith et al., 2022), indicative distribution maps Keith et al. (2020), https://doi.org/10.5281/zenodo.3546513; Large Marine Ecosystems — NOAA LME Program; Bathymetry — GEBCO Bathymetric Compilation Group (2026), GEBCO_2026 Grid, https://doi.org/10.5285/4f68d5c7-45eb-f999-e063-7086abc036fa; Climate data — Generated using Copernicus Climate Change Service information; Species occurrence data — GBIF.org, Derived dataset "all animals", https://zveriki.com/dataset/dataset.tsv; Terrestrial ecoregions — RESOLVE Ecoregions 2017 (Dinerstein et al., 2017), CC BY 4.0
How to care for them?
Living from 25 to 40 years. Orangutans, bald eagles, African elephants celebrate their birthday twice a year
°C
Not specified
small mollusks
Actively searching habitats to locate food items.
Egg color
pelagic zone — open water far from shore and seabed
Where are they found?
all seas and oceans
Pectoral fins size
Species lacks any fixed or lasting shelter structure.
Locomotion through water employed while searching for or capturing prey.
Legendary longevity: over 100 years. Galapagos tortoises, Greenland sharks, ocean quahogs celebrate with family once every 4 years
Offspring
Elders
Bro
Taxons
carnivore
if born as {name}
biotope of coral and rocky reefs
age
birth date
Palearctic realm
swimming
no permanent shelter
Close
was
Career from 7 to 15 months. Dwarf hamsters, voles, field crickets celebrate their birthday twice a month
Marine world
marine epipelagic
The basics
My weight?
Non-stop carnival: they only live a few days. Mayflies, rotifers, midges celebrate their birthday more than twice a day
Dorsal spine color
primary food sources
Temperate sea
Potential Habitat
d
In husbandry
On the go from 1.3 to 3.5 years. Forest mice, anoles, rainbow fish party on their birthday once a month
Feeding occurs in water bodies such as rivers, lakes, or oceans.
Mass
Mosquitoes, fruit flies, small crustaceans hustle for up to 7 months and throw a birthday party every week
Gestation
from 130 grams to 0.5 kilograms, 0.35 – 0.8 meters
Body size
aquatic
{name} birthday
live annelid worms
No results found
On the map
lunge
all life stages
Female ♀
Body color
Map data sources: Ecosystem classification — IUCN Global Ecosystem Typology (Keith et al., 2022), indicative distribution maps Keith et al. (2020), https://doi.org/10.5281/zenodo.3546513; Large Marine Ecosystems — NOAA LME Program; Bathymetry — GEBCO Bathymetric Compilation Group (2026), GEBCO_2026 Grid, https://doi.org/10.5285/4f68d5c7-45eb-f999-e063-7086abc036fa; Climate data — Generated using Copernicus Climate Change Service information; Species occurrence data — GBIF.org, Derived dataset "all animals", https://zveriki.com/dataset/dataset.tsv; Terrestrial ecoregions — RESOLVE Ecoregions 2017 (Dinerstein et al., 2017), CC BY 4.0
Potential habitat modelled from GBIF occurrence data. Map © Zveriki.com, licensed under CC BY 4.0.
birth year
Maturity
Skin color
sq mm
yr
Body count
How similar?
Egg size
Male ♂
until the celebration
age as {name}
How do they breed?
On the go from 3.5 to 6 years. Hedgehogs, crows, lizards treat themselves to birthday snacks 6 times a year
What if eaten?
Neither
from birth to adulthood
Skin count
What do they eat?
Where do they live?
Immature individual that has not yet reached reproductive maturity.
Marine world
early young
Duration
Pectoral fins color
saline marine habitat
This is me
Gamers
How are they built?
marine
shallow near the shore, water rises and falls, crabs live here
mm
Theoretical lifespan
ml
Stars
Link copied
coastal marine zone — shelf, neritic zone
My age?
wk
My size?
Asexual
swap
active predation
Rabbits, falcons, red-eared turtles hang out for 6-9 years and party on their birthday four times a year
Where do they take shelter?
celebrated their {n} birthday
When you would have been born if you lived as {name}
Littoral Zone
Daddies
Lifespan maximum
foraging
from development to end of fast growth
Hermaphrodite ⚥
shrimp
embryo
Zucchini
Length
kg
Rapid forward strike to seize prey.
Observations
◉{N} more on tap