Medium to very large turtles with a round (hatchling) to oval
(adult) skin-covered flattened carapace without scutes or keeling. In the hand
they feel something like wet leather. The carapace (which extends back a good
deal further than in our basking species) is flexible, & the posterior lip hangs
a bit in some adults. The head has fairly high-set eyes & a long, almost
snorkel-like nose giving them a ‘needle-nose’ or ‘Pinnochio’ face. The head
enjoys excellent mobility on the neck, & softies can rise up from underwater &
set the head with eyes & nose just above the surface, like an alligator. The
neck is unusually long & rather thick. Spiny softshells take their name from
small ‘thorn-like’ spines at the anterior carapace, prominent in some adults but
harder to detect in juveniles. The carapace & skin match in color; variably tan
to muddy-brown to olive, with spots or ocelli prominent on juveniles & some
males but less distinct in larger females. The adult carapace can have a strong
mottled, ‘muddy’ patterning. There may be limited striping on the head & neck.
Softshells can darken & lighten their color a great deal over time to better
match their habitat. The underside of the shell is while (yellow in some); the
undersides of the limbs may be lighter as well. The plastron is hinge-less &
reduced compared to the carapace. The toes are clawed & prominently webbed, &
the feet have an oar-like appearance. Large specimens can inflict severe
Softshells (all species) stand out amongst North American
turtles in having fleshy lips. In large adults this feature may be a bit
exaggerated. Be warned - right behind those lips are hard, sharp jaws
that can put you in stitches.
A prominent distinguishing feature of spiny softshells is the
presence of a nasal septum lateral ridge’ – a small ‘bump’ on either side of the
septum extending slightly into the nostril (pictured above). This aids in
distinguishing spiny from smooth softshells. However, Florida softshells also
have this ridge & Guadalupe spiny softshells may not (per Tom C. & Snapper
Greg). Florida softshells lack anterior carapacial spines but have blunt
knob-like bumps instead.
Male spiny softshells have larger, longer tails with the anus
near the tip & are more prone to retain the vivid coloration & patterning of
juveniles. They lack the elongated fore-claws typical of male sliders & cooters.
Females get much larger than males.
We must emphasize that females can get massive by
hobbyist standards. Males are hardly ‘small,’ but large females of this alert,
active species are challenging to house. You must see a large female to
The 6 U.S. occurring sub-species: South-Central &
South-Eastern U.S., with some branching & isolated populations in the southwest.
There’s a disconnected group covering part of Montana. Strangely in the eastern
states north of South Caroline (NC, VA, MD, DE, NJ) they are either absent or
restricted to the western edges (& southern NC). NY & Vermont have some. Spiny
softshells do penetrate slightly into extreme southeastern Canada.
Adult Sizes: Male
5" - 9½" Female
6½" – 18"
Apalone spinifera spinifera
Probably the best-known spiny softshell in the pet trade, & so the
‘stereotype’ of the group.
Turtles of the United States & Canada1,
Page 114 distinguishes is from the other sub-species by large black ocelli
(eye-like spots) in combo. with only one dark marginal line (thin black
‘outline’ around the carapace rim, seen from above).
East-central U.S., from western edges of NY, PA, WV,
slightly VA & NC sweeping westward across OH, IN, IL, KY, TN & northern AL
& NW MS to cross the Mississippi River into eastern IA, MO & AR. Some in
WI. Some overlap with Western & Pallid spinies.
Apalone spinifera hartwegi
The black spots on the carapace are uniform and smaller
than in Easterns. It displays only a single marginal line.
Central U.S. west of the Mississippi river; some over-lap
with Eastern spinies along the western river border region. Occur over
much of IA, MO, northern AR & east & central NE, KS & OK. Population
extends ‘fingers’ southwestward into WY, CO, & a bit into north TX & NM.
Isolated population in MT.
Coast Spiny Softshell
Apalone spinifera aspera
Per Peterson’s Field Guide to Reptiles and Amphibians of
East/Central North America8, Pages 196-197, the 2 lateral
head stripes in Gulf Coast spiny softshells usually meet further back on
the head (those on Eastern spinies don’t) & 2 dark lines parallel the rear
carapace margin (all other spinies have one).
Southeastern US covering much of MS, AL, GA, SC & also in
western LA & south-central NC. Also found in the FL panhandle but nowhere
in the peninsular portion of the state. Some overlap with Eastern & Pallid
Guadalupe Spiny Softshell
Apalone spinifera guadalupensis
Turtles of the United States & Canada1,
Page 116 states they live only in
Nueces & Guadalupe-San Antonion watersheds in south-central Texas. Tom C. &
SnapperGreg noted Guadalupe’s may lack the nasal septal ridge of other spinies.
White tubercles surrounded by narrow black circles on the back 1/3 of the
carapace, some tubercles can be quite large. It also may have some black
dots spread out amongst the white tubercles.
A relatively small range in southern Texas, consisting of
the Nueces and Guadalupe-San Antonio drainage systems of south-central
Apalone spinifera pallida
It is pale and has white tubercles on the posterior half of
the carapace. These tubercles descrease in size gradually towards the back
end of the carapace and become indistinct or absent at the back 1/3. These
tubercles are not surrounded by black circles.
A south-central range overing southern OK & AR, northeastern
TX, & most of LA. Can be found in the upper Red River drainage and in the
rivers that drain into the Gulf of Mexico east of the Brazos River in
Apalone spinifera emoryi
The carapace is surrounded by a pale rim that is up to four
or five times wider on the back than it is along the sides. It has a
slightly curved line connecting the back margins of the eyes and the
stripes behind the eyes are usually interrupted, leaving a pale blotch
behind each eye.
Range is much more ‘long & narrow’ than other varieties,
largest in Texas but veering westward to parts of NM, AZ, & the western AZ
border touching CA, NV & UT. Some occurrence in northern Mexico. Can be
found in the Rio Grande drainage in Texas and New Mexico and the Colorado
River drainages in Arizona, New Mexico, southwestern Chihuahua, central
Coahuila, northern Nuevo Leon and Tamaulipas.
Apalone spinifera ater
This softshell is dark gray or brownish-black with a gritty
to smooth carapace. The back portion of the carapace is wrinkled and
creased with a ragged edge and sports no tubercles on the back rim. The
plastron displays numerous black specks.
Restricted to permanent ponds in the Cuatro Cienegas basin
in Coahuila, Mexico.
|* This section interpreted from info.
in Peterson’s Field Guide to Reptiles and Amphibians of East/Central North
America8, Page 198 - 3 sub-species characterized by small white
spots on the carapace (females beyond juvenile stage often lack them). In
Guadalupes, white spots occur on almost all parts of carapace & often ringed in
black. In Pallid spinies, white spots largely confined to posterior half of
carapace & not ringed in black. In Texas spinies, white spots largely confined
to rear third of carapace, which has a widened pale rim.
TEMPERATURE RANGE (°F)
- Air Temperature: Low to Mid 80's
Basking Temperature: Mid
to High 80's
Water Temperature: Mid 70's
CARE DIFFICULTY - MALE
CARE DIFFICULTY - FEMALE
Softshell keepers should have a solid understanding of water
quality, filtration, cover & substrate issues, coupled with the resources to
provide spacious enclosures.
In the wild, they are predominant carnivores utilizing a wide
prey-base varied with availability, including insects & insect larvae, crayfish
& other crustaceans, small fish (live), larger fish (carrion), snails, mussels,
frogs and worms. Some take in some vegetation. Don’t over-generalize from single
locale population studies, but do consider Turtles of the United States and
Canada1 Page 122-cited research (Williams & Christiansen, 1981)2
on the diet of spiny softies in Iowa – 36.5% fish (likely carrion), 5.8% small
fish (likely caught) & 55% crayfish; 61% of spinies sampled contained plant
matter. The % by volume was 24.2% crayfish, 17.2% large fish (remember; likely
carrion), 2.2% small fish, 12.8% plant matter, & 21.6% as insects/insect larvae
(i.e.: mayflies, beetles, Hemipterans ‘true bugs,’ dragon flies & damsel flies,
caddisflies & some unidentifiable insect material), 19.5% unidentified animal
matter & 2.0% sand &/or gravel. Also cited is research by Breckenridge (1944)3
on 18 spinies in Minnesota who contained 44% crayfish, 29% aquatic insects & 8%
fish. So in nature the diet is overwhelmingly small invertebrates (insects &
crayfish) supplemented with small fish, fish carrion & other items (i.e.: snails
& mussels). Spiny softshells actively hunt but also ambush prey.
spiny softshells tend to favor carnivorous food items like aquatic turtle
pellets, grasshoppers, crickets, ghost shrimp, small crayfish, small fish, earth
worms & blood worms. They may show little interest in aquatic plants or Romaine
lettuce but will eat Spirulina algae wafers & commercial tortoise
pellets. A youngster may be slow to warm to commercial pellets. We recommend you
don’t use wild snails (known to be intermediate vectors of a number of indirect
life cycle parasites affecting a range of animals, & snails of the genus
Goniobasis are known to transmit lung flukes to loggerhead musk turtles5).
If you don’t provide UV-B lighting, make sure the diet includes Vitamin D3
sources such as a brand name commercial food (i.e.: ReptoMin or Mazuri aquatic
RECOMMENDED FEEDING SCHEDULE
For the first 6 months of life, feed
commercial pellets or meaty foods such as earthworms or fish in moderation once
daily, enough to diminish appetite but not gorge the turtle. After 6 months,
switch to every other daily feeding. Romaine lettuce & other leafy greens may be
offered daily for graze at will (if your softy is an odd-ball & likes plants).
Over time adjust diet content & schedule accounting for growth, activity level &
appetite. Overfeeding high-protein foods can cause rapid growth & is believed
harmful to the liver & kidneys. Softshells lack the keratinized plates (scutes)
of hard-shelled species & I’ve not heard of shell deformities (pyramiding) from
over-feeding as basking turtles may suffer, but they can still suffer metabolic
bone disease (MBD) like any reptile.
It is critical you do not gorge
your juvenile softshell. We have had reports of both smooth & spiny
softshell juveniles abruptly dying shortly after gorging on food. The mechanism
is unknown (Timdog speculated so much food may cause a drop in abdominal space
preventing lung expansion, but we don’t know).
Wild softshells are heavily aquatic & seldom leave the water
except to lay eggs or bask (they are at serious risk for dehydration if out of
water long). Turtles of the United States & Canada1 Pages
117-118 claims they are predominantly a riverine species (also inhabiting marshy
creeks, bayous, oxbows, lakes & impoundments), & states a soft bottom with some
aquatic vegetation seems essential (& sandbars & mud flats are usually present).
The Amphibians and Reptiles of Arkansas6 Page 241 states they
inhabit a wider variety of habitats, & are more prone to bask on emergent rocks,
logs & other objects, than smooth softshells. Turtles of the United States &
Canada1 also states the preferred microhabitat appears dominated
by areas with much submerged brush, fallen trees & other debris. I found an
adult in a creek under 10 feet wide, & many live in our neighboring Little River
in SW KY, including area around 20-30 feet wide & 1-3 feet deep. I can view the
most wild Eastern spiny softshells in large stream-like habitat with steep,
grassy but not badly overgrown banks & good sun exposure. I have not found the
lack of brush & debris to be a problem. They bask on muddy banks at the water’s
edge, often right on the water line, facing the water & ready to dart in. Rocks
& even logs may be used. Wild spiny softshells are vigilant & wary, quick to
slide in when humans are still many yards away (as befits an animal with no
hard-shelled protection). Unlike with sliders, field herping spiny softshells is
an acquired skill. One common feature of spiny softshell habitats seems to be
moving (hence better oxygenated) water; I’ve seen them in creeks & rivers but
not static water bodies like farm ponds. Turtles of the United States &
Canada1 Pages 118-119 indicates they’re strongly diurnal & at
night sleep buried in bottom substrate or amid branches of submerged trees.
In southwestern KY Wallob & I have noted softshells are the last aquatic turtles
to come out in Spring & the first to disappear in the Fall (compared to RES,
stinkpots & common snappers).
In captivity, spiny softshells
need spacious enclosures with pristine water quality, cover to feel secure (such
as live or plastic plants) & a basking platform. They are apt to burrow into
sand or muddy bottoms, & given the chance may extend the neck up for air without
coming out (looks rather like a very strange needle-nosed snake). ‘Play Sand’
(sold at Home Depot & other vendors) is widely used for softshells. Sand sucked
into your filter’s intake can damage the impeller, so if you use sand keep the
intake at least 5” above the sand bed & ideally put a pre-filter sponge on your
intake. Small gravel is an alternative less prone to get sucked into filters but
your Python or gravel vacuum will suck it up more so than larger gravel. Some
keepers compromise & offer a bowl or basin of sand in the tank; be warned it’ll
get out! For no substrate or non-burrowable substrate tanks, supporting cover is
important; aim for a ‘jungle look’ with submerged plastic &/or live plants.
Softshells are vulnerable to bacterial & fungal infections starting with
scratches & nicks from tank contents or other turtles; hence, avoid abrasive
tank contents, crowding & poor water quality. If your animal seems
infection-prone consider a UV-Sterilizer. Their burrowing may uproot plants;
consider such plants as Anacharis or some Salvinia that require no
substrate. In deference to their natural flowing, well-aerated habitat, direct
your filter’s outflow to provide surface flow/turbulence. In Keeping and
Breeding Freshwater Turtles7 Page 127, Russ Gurley indicated
adding 1 teaspoon aquarium salt per gallon water can be beneficial.
Someone reported keeping softshells in outdoor concrete ponds
where they prospered & speculated that natural sunlight may’ve enabled them to
shrug off the nicks & scratches concrete brings. I don’t recommend concrete or
brick in softy tanks, but be aware. If you must use concrete, consider sealing
it with something like marine epoxy, which coats & smooths.
Recommended size for a single adult Apalone spinifera
would be a 75 gallon aquarium as a minimum (90 or larger preferred) for a male.
We don’t recommended large females be kept in conventional aquariums. They are
too large & active and require extreme amounts of space. Stock tanks are an
option, with a minimum requirement of 400 gallons (600 gallon or larger
preferred). This will provide adequate swimming space & assist the filtration in
maintaining good water quality. For additional males, we recommend adding
a minimum 75 gallons of tank space per additional turtle. For females, add no
less than 100 gallons of space per turtle.
With these space recommendations you may consider a swimming
pool. Be sure you get one with great structural stability.
At least 1.25x’s the SCL of an
adult, & preferably deeper, up to 4 feet or more. A shallow ‘shelf’ area for
resting near the surface will be appreciated, particularly if it offers a
container of sand to burrow in.
Turtles of the United States & Canada1
Page 120 states spiny softshells are aggressive toward their own species, the
larger tend to dominate the smaller in captive interactions (invariably
involving a considerable amount of biting) & yet they’re usually not pugnacious
with hard-shelled turtles. In Keeping and Breeding Freshwater Turtles7
Page 127, Russ Gurley notes they are somewhat aggressive, especially to smaller
softshelled turtles. Bill Ninesling of Indian River Reptile, Inc. once told me
they’re often tail nippers. Tom noted there have been
those that have had success keeping them with Musk Turtles, Sliders, Cooters,
Map Turtles and Painted Turtles. He has kept 2 separate male spiny
softshells with hard-shelled tank mates (but not each other) without problems.
Some people do mix them. Visual barriers in large tanks may help but no home
aquarium is large enough to thwart a determined aggressor. Softshells’ thin
noses are vulnerable to fights over food, & the slim, soft shells are easily
injured. Such injuries are infection-prone.
We recommend keeping softies alone or in spacious enclosures
with strong filtration, no crowding & no aggressive tank mates. Watch closely
when first mixing.
Unlike many of their hard-shelled brethren, spiny soft-shell
turtles do not exhibit temperature-dependent sex determination & clutches will
produce roughly 50/50 mixes under a range of conditions. Females are large
enough to lay large clutches. Keeping and Breeding Freshwater Turtles7
Page 272 gives typical artificial incubation time at around 55-60 days at 82ºF &
75-85% humidity. Considering that spiny softshells have large clutches, are
demanding to keep long-term, neither threatened nor endangered, in good supply
in the hobby, & command low prices, it is not recommended you breed them.
Hatchlings softshells are delicate; in Keeping and Breeding
Freshwater Turtles7 Page 126, Russ Gurley opines they are
probably the most sensitive hatchling turtles in captivity re: captive care. In
Practical Encyclopedia of Keeping and Breeding Tortoises and Freshwater Turtles9
Page 256 A. C. Highfield recommended both high quality external filtration & UV
sterilization to reduce risk of slight injuries becoming infected.
Keeping wastes dilute & filtration strong is easiest in large
water volumes. While a 20 gallon long tank 2/3’rds filled is acceptable, the
larger the tank the better water quality is apt to be. Provide real (if you have
strong lighting) or artificial plants for cover, & ideally either a sand
substrate or bowl of sand for hiding to foster a sense of security. Aim for
water temp. 80ºF & offer a non-abrasive basking platform. UV-B lighting is
recommended. If you have more than one in an enclosure, watch for aggression,
injuries & avoid over-feeding. We recommend a UV sterilizer at least on smaller
enclosures or those with a number of turtles.
Spiny Softshell turtles can be aggressive when handled. Larger
specimens’ jaws can lacerate you badly enough to require stitches, & their claws
can on occasion penetrate skin. They have a long reach & often struggle
vigorously when handled.
The 6 spiny softshell sub-species native to the U.S.A. range
from neotropically warm extreme southern US & even northern Mexico all the way
to extreme southeastern Canada. Don’t expect a Texas softshell from northern
Mexico to handle overwintering in the harsh climate of Montana! Be mindful of
sub-species & ‘climate of origin’ if outdoor keeping is expected (with females,
it always is).
Turtles of the United States & Canada1
Page 119 cites research (Bentley and Schmidt-Nielsen, 1970)4 that
spiny softshells’ skin is 3 or 4 times more permeable to water than sliders.’ Be
mindful of that if you need dry dock one, or it escapes its enclosure. I don’t
see spiny softshells wandering on land the way I see common snappers & RES do.
Keeping and Breeding Freshwater Turtles7
Page2 124-125, Russ Gurley states successfully keeping softshells is very
difficult & recommends keepers keep Acriflavine & Silvadene cream on hand for
emergencies. Softshells are more sensitive to Betadine than hard-shelled
turtles. You can treat some conditions with it, but don’t overdo it.
It is possible to sex young juvenile spiny
softshells, albeit a few months after hatching. Hatchling spiny softshells (both
sexes) typically have prominent spots & ocelli (rings around spots). In females
over time the rings disperse to become smudgy halos, then continue dispersion to
form muddy patches/blotches reminiscent of lichen patches on a rock. Hatchlings
are roughly 30-40 mm SCL1. Terry Graham10 reported
examining about 60 Eastern Spiny hatchlings in Vermont with none displaying a
blotched (female) pattern. In a head-start program he later observed 6 Eastern
Spiny hatchlings over 4 months, & 2 developed female patterning (the first
indication being the smudgy halo around each ocellus) at around SCL 52 mm (a bit
> 2”). Regarding the Gulf Coast Spiny Softshell, Webb11 cited the
largest females with no blotched pattern were PL (plastron length) 7.6 cm & 8.0
cm (SCL would’ve been a bit longer). In summary, while this method is not
full-proof, for juvenile Eastern spiny softshells > 2” SCL well-defined rings/ocelli
with no smudging appear strongly suggestive of males, whereas ring-smudging &
blotchiness is strongly suggestive of a female.
Turtles of the United States and Canada
– Carl H. Ernst, Jeffrey E.
Lovich and Roger W. Barbour. Smithsonian Institution Press, Washington and
London. ©1994. (Possibly the preeminent natural history text of North American
turtles – very highly recommended. Note it uses an older naming system for North
American soft-shells). 682 pp.
Williams, T. A., and J.
L. Christiansen. 1981. The niches of two sympatric softshell turtles, Trionyx
muticus and Trionyx spiniferus, in Iowa. J. Herpetol. 15:303-308 ((cited
in Turtles of the United States and Canada, Page 122).
Breckenridge, W. J. 1944.
Reptiles and amphibians of Minnesota. Univ. Minnesota Press, Minneapolis. 202
pp. ((cited in Turtles of the United States and
Canada, Page 122).
Bentley, P. J., and K. Schmidt-Nielsen. 1970.
Comparison of the water exchange in two aquatic turtles, Trionyx spinifer
and Pseudemys scripta. Comp. Bio-chem. Physiol. 32:363-365 (cited in
Turtles of the United States and Canada, Page 119).
Cox, W. A., S. T. Wyatt, W. E. Wilhelm, and K. R.
Marion. 1988. Infection of the turtle, Sternotherus minor, by the lung fluke,
Heronimus mollis: incidence of infection and correlations to host life history
and ecology in a Florida spring. J. Herpetol. 22:488-490 (cited in Turtles of
the United States and Canada, Page 160).
The Amphibians and Reptiles of Arkansas
– Stanley E. Trauth, Henry W. Robison and Michael V. Plummer. University of
Arkansas Press. © 2004. (Billed
as the product of 15 years of work by top herpetologists, features over 136
species & sub-species).
Keeping and Breeding Freshwater Turtles
Russ Gurley. Living Art Publishing, Ada, Oklahoma.
©2003. (Excellent advanced general care guide). 300 pp.
Reptiles and Amphibians of Eastern/Central North
America – Peterson’s Field Guide Series – Roger Conant
and Joseph T. Collins. 3’rd Ed., expanded. Houghton Mifflin Company, Boston, New
Practical Encyclopedia of Keeping and Breeding
Tortoises and Freshwater Turtles – A. C. Highfield.
Carapace Press, London, England.
©1996. (The definitive general chelonian husbandry guide for years; the only
serious competitor I’ve seen is Gurley’s book1).
Graham, T. E. and C. B.
Cobb. 1998. Sexual dimorphism of neonate eastern spiny softshells, Apalone
spinifera. Chelonian Cons.Biol. 3:111-112.
Webb 1992. Univ. Kansas
Publ. Mus. Nat. Hist. 13:429-611).