The carapace of Pagurus
hirsutiusculus has setae
but no spines, and only the shield
is calcified (photo).
is about as wide or wider than it is long. The carpus
of the right cheliped
is wider than it is long and is not strongly flattened (photo).
of legs 2 and 3 is not twisted. It does not have longitudinal
or white stripes, but does have some red stripes (photo).
The dorsal surface of the left chela
does not have a prominent ridge or crest, nor a concavity near the
The ventral surface of the merus of the right cheliped
has one prominent tubercle,
but it is often obscured by the abundant setae
(photo). The chelae
do not have stout spines but have closely spaced tubercles,
granules, and setae
The ventral side of the
of the right cheliped
is not greatly swollen. The long second antennae are mainly
with yellow or white bands or spots (photo).
The legs are greenish brown with many setae
(photo), and legs
2 and 3 have white
or bluish bands at the articulation of the propodus
(photo), and usually a blue
dot at the upper end
of the propodus
(may also have a blue dot on the dactyl)
Overall color olive green,
brown, or black Carapace
length to 19 mm.
Pagurus hirsutiusculus (Dana,
Common name(s): Hairy hermit
Bernhardus hirsutiusculus, Eupagurus hirsutiusculus, Pagurus
hirsutiusculus, Eupagurus mertensi
|Pagurus hirsutiusculus from
the Rosario area
|(Photo by: Dave
Cowles, August 2005)
How to Distinguish
from Similar Species: Pagurus
hemphilli is mostly similar but has orange-red
antennae. Of the
very common intertidal species, P.
granosimanus has olive-green legs with small blue
samuelis has a bright blue dactyl
on legs 2 and 3 instead of just a blue band, plus it occurs mainly on
open coast. P.
is often mistaken for a small P. hirsutiusculus,
caurinus has spines on its chelae
and its 2nd antennae are reddish brown without spots.
Range: Pribilof Islands, Alaska
to Monterey, CA; Siberia, Japan; smaller and less hairy south of Puget
Sound, and even more so south of Monterey Bay. Common in San
Depth Range: Intertidal
to 110 m
tide pools and under
rocks and algae, more abundant in protected water.
This species is
less resistant to emersion than is P.
granosimanus, but it is more tolerant of brackish
Many occupy small, light shells which they cannot completely retract
They will also abandon their shell more readily than do some other
such as P.
(photo), sometimes even
when they are berried
(carrying eggs (photo).
They seem to
have definite shell preferences, but these may be different in
places. Favorites include Nucella
spp, and Olivella
biplicata shells. Diet is mainly
detritus, though they will
eat live prey opportunistically. It is known to feed on
emarginata, which lay and attach their eggs in the
Predators include sculpins. Females become ovigerous in late
and carry a total of about 5 broods through spring and
include the parasitic barnacles Peltogaster paguri
gracilis and the bopyrid isopod Pseudione giardi.
and Fairbanks, 1966
and Carlton, 1975
and Brusca, 1978
and Snook, 1955
et al., 1980
and O'Clair, 1998
et al., 1985
General Notes and
Observations: Locations, abundances,
Although Pagurus hirsutiusculus is
often the most common intertidal
hermit crab in this region, we find few of these on Sares
this is because P. hirsutiusculus is most common in
and Sares Head has few tide pools except in the very low
There are plenty of rocks they could hide beneath, though.
much more common on the protected side of Fidalgo Island, around rocks
in Padilla Bay.
Another individual from Sares Head.
of P. hirsutiusculus has setae
but no spines. The front part (shield),
which is the only part which is calcified, is about as wide as it is
In this photo the
of the carapace
is to the top right, behind the eyestalks.
In this view of the chelae,
legs, and second antennae, one can see the setae
which cover the chelae
and legs, the larger right chela
which is characteristic of Pagurus,
and the fact that the carpus
of the right chela
is slightly longer than wide and it is not flattened. The
are green with white bands.
of legs 2 and 3 are not twisted, and there is a white (or blue) band at
the junction of the propodus
surface of the right merus
(center of photo) has one prominent
but it is largely obscured by the abundant setae.
This individual jumped out of its shell which was stuck. That
makes it easy to see the abundant body and leg setae.
Photo by Dave Cowles July 2008
This female readily crawled out of her shell even though she is
(carrying eggs under her abdomen).
Photo by Dave Cowles at Kalaloch Beach #4, July 2009
The eyes of Pagurus hirsutiusculus generally seem
to have a
dark crescent-shaped band in them, as can be seen in this closeup
view of the head.
Photo by Dave Cowles July 2008
This individual has both white bands and blue spots on
Photo by Dave Cowles, July 2010
|Occasionally individuals are
encountered with barnacles
growing on them. The individual on the left above is carrying
but has a strong encrustation of barnacles on its carapace
and on several legs. The individual on the right was
running around without a shell and has a very heavy growth of barnacles
on its carapace and several on its legs. The barnacles appear
be so large that it would be difficult for either of these individuals
to find a shell large enough that they could withdraw into, though the
left individual can at least tuck its abdomen into its shell.
were found in tidepools at Beach #4, Kalaloch, WA. Photos by
Cowles, July 2012.
This juvenile, which apparently hitched a ride on something else into
my classroom tank, is small and has few hairy setae
on the legs yet but already is developing the white bands on the distal
ends of the propodus
of the walking legs and the blue spot on the proximal end. It
selected a Littorina
scutulata shell, 8 mm long, for its
home. Photo by Dave
Cowles, August 2016.
Authors and Editors of Page:
Dave Cowles (2005): Created original page