Apalone mutica
(LeSueur 1827)

ā-pă-lō'-nē — mŭ-tĭ-kă

An adult female Smooth Softshell from Labette County. Image © MaxEweleen Hornbuckle Good, 2018.
An adult male Smooth Softshell. Image by Suzanne L. Collins, CNAH.
An adult female Smooth Softshell from Kingman County, Kansas. Image © Ken Brunson.

Softshell turtles are characterized by flat, flexible carapaces, and plastrons that are much smaller than the upper. Smooth Softshells lack fleshy bumps or tubercles along the front edge of the carapace. Limbs are typically uniform brown in color, and a yellow or white line extends through the eye on each side of the head. Males have much longer heads.
Adults normally 115-306 mm (4½-12 inches) in carapace length; largest specimen from Kansas: female (KU 218796) from Osage County with carapace length of 285 mm (11¼ inches) collected by John Powell and Beverly Downing on 9 June 1991; maximum carapace length throughout range: 14 inches (Conant and Collins, 1998).

Smooth softshells are found in rivers, large streams, and, rarely, large lakes with sandy or muddy bottoms. These lakes are usually close to a large river. Sandbars are important for basking and egg laying sites. They seem to prefer larger rivers and live in colonies along certain portions
Historic records indicate that the Smooth Softshell once occurred statewide.

Locality Dot Map:
The brown shaded areas () show the boundaries of properties in public or institutional ownership that contain ecological resources that merit some level of protection (KBS file).
(, Museum Voucher) (, Observation) (, Literature Record). Export Google Earth (.kml)
Open icons indicate questionable records; Click on a marker to view details.
  • Occurrence Summary:  
  • 276 Total Records 
  • 253 Museum Vouchers 
  • 23 Other Observations 
County Breakdown: County Name (# occurrences): Some occurrences indicated below may be too imprecise to map.
Atchison (2); Barber (4); Comanche (1); Cowley (10); Crawford (1); Dickinson (1); Doniphan (2); Douglas (29); Ellis (4); Ellsworth (1); Finney (1); Geary (1); Harvey (2); Johnson (1); Kearney (1); Kingman (4); Leavenworth (166); Lyon (1); Marshall (1); Neosho (1); Osage (1); Pottawatomie (7); Reno (5); Riley (8); Russell (4); Sedgwick (6); Stafford (1); Sumner (6); Trego (1); Unknown (1); Washington (1); Woodson (1);

Natural History:
Smooth Softshells prefer moving water, rarely leaving except to bask or nest. Nesting typically peaks in May to June and females will deposit clutches of 3-25 eggs. Eggs typically hatch in 2 to 2 ½ months. Smooth Softshells are primarily carnivorous. Males may consume more terrestrial prey than females. The two sexes exhibit some differentiation of habitat, with males occurring more often in shallow water along shorelines, while females prefer deeper water.

Occurrence Activity:
Most Kansas specimens were collected from the Kansas River below the low water dam at Lawrence, in association with the doctoral research of Dr. Michael Plummer (Fitch and Plummer, 1975; Plummer, 1975, 1977, 1977) and most of our information on the natural history of this species are due to his efforts.
The remainder of the known occurrences are widely scattered across the state. Despite numerous attempts to document this turtle during the study, only one specimen was discovered. Possible reasons for this putative decline are unknown.
Cornelius Rogers took this species on a sandbar at the junction of a small creek and Medicine River, a little less than 5 miles southeast of Lake City, Barber County, Kansas, on August 30, 1934. The form was taken on a bank of Salt River just south of Aetna in the same county on April 21, 1934. Also, on May 25, 1934, an example was secured 6 miles east of Turon, Reno County, Kansas, in a shallow sand-bottomed, algae-filled pasture streamlet (Burt, 1935).
Smooth Softshells may be taken year-round. Daily creel limit is eight turtles, single species or in combination (with Spiny Softshells and/or Snapping Turtles). Possession limit is three creel limits. A valid fishing license is required (unless exempt [e.g. < 16 years of age]). Legal equipment: hand, hook and line, setline, hand dip net, seine, turtle trap, or gig.

1933 Stejneger, Leonhard and Thomas Barbour. A Checklist of North American Amphibians and Reptiles. 3rd Edition. Harvard University Press, Cambridge,Massachusetts. pp.
1933 Taylor, Edward H. Observations on the courtship of turtles. University of Kansas Science Bulletin 21(6):269-271
1935 Burt, Charles E. Further records of the ecology and distribution of amphibians and reptiles in the middle west. American Midland Naturalist 16(3):311-366
1947 Smith, Hobart M. Kyphosis and other variations in soft-shelled turtles. University of Kansas Publications Museum of Natural History 1(6):117-124
1956 Clarke, Robert F. Identification of Kansas turtles. Kansas School Naturalist 2(4):1-3
1956 Clarke, Robert F. Turtles in Kansas. Kansas School Naturalist 2(4):1-15
1962 Gish, Charles D. The Herpetofauna of Ellis County, Kansas. Thesis. Fort Hays State University, Hays, Kansas. 34pp.
1974 Collins, Joseph T. Amphibians and Reptiles in Kansas University of Kansas Museum of Natural History Public Education Series (1):283 pp
1975 Fitch, Henry S. and Michael V. Plummer. A preliminary ecological study of the softshelled turtle Trionyx muticus in the Kansas River. Israel Journal of Zoology 24():28-42
1975 Plummer, Michael V. Population ecology of the softshell turtle, Trionyx muticus Doctoral Thesis, University of Kansas ():173
1975 Plummer, Michael V. and Hampton W. Shirer. Movement patterns in a river population of the soft-shell turtle, Trionyx muticus. Occasional Papers of the Museum of Natural History, The University of Kansas (43):1-26
1975 Rundquist, Eric M. First KHS field trip yields three county records. Kansas Herpetological Society Newsletter (7):1-3
1976 Plummer, Michael V. Some aspects of nesting success in the turtle, Trionyx muticus. Herpetologica 32(4):353-359
1977 Plummer, Michael V. Activity, habitat and population structure in the turtle, Trionyx muticus. Copeia 1977(3):431-440
1977 Plummer, Michael V. Notes on the courtship and mating behavior of the softshell turtle, Trionyx muticus (Reptilia, Testudines, Trionychidae). Journal of Herpetology 11(1):90-92
1977 Plummer, Michael V. Reproduction and growth in the turtle, Trionyx muticus. Copeia 1977(3):440-447
1980 Clarke, Robert F. Herptiles and fishes of the western Arkansas River in Kansas. United States Army Corps of Engineers, Albuquerque, New Mexico. 55pp.
1981 Bovee, E. C. New epizoic suctorea (Protozoa) of the Smooth Softshell Turtle, Trionyx muticus, in northeastern Kansas. Transactions of the Kansas Academy of Science 84():98-104
1992 Edds, David R. Population status and incidence of anatomical abnormalities in semiaquatic turtles of the Walnut and lower Arkansas river basins. Kansas Department of Wildlife and Parks, Pratt. 58pp.
1993 Collins, Joseph T. and Suzanne L. Collins. Amphibians and Reptiles in Kansas. Third Edition. University Press of Kansas, Lawrence, Lawrence. 397pp.
1998 Collins, Joseph T. New records of amphibians and reptiles in Kansas for 1997. Kansas Herpetological Society Newsletter (111):12-14
2001 Collins, Joseph T. New records of amphibians and reptiles in Kansas for 2000. Kansas Herpetological Society Newsletter (124):6-8
2006 Taggart, Travis W. Distribution and status of Kansas herpetofauna in need of information. State Wildlife Grant T7. Kansas Department of Wildlife and Parks, Pratt. vii + 106pp.
2010 Collins, Joseph T., Suzanne L. Collins, and Travis W. Taggart. Amphibians, Reptiles, and Turtles of Kansas Eagle Mountain Publishing., Provo, Utah. 400pp.
2010 Miller, Larry L. 2010 Investigation of the Checkered Garter Snake in Kansas with notes on other Amphibians, Reptiles, and Turtles encountered. Kansas Department of Wildlife and Parks, Pratt, Kansas. 31pp.
2012 Rohweder, Megan R. Spatial conservation prioritization of Kansas for terrestrial vertebrates. Thesis. Fort Hays State University, Hays, Kansas. 151pp.
Account Last Updated:
7/25/2019 10:39:09 AM

Travis W. Taggart © 2019 — Sternberg Museum of Natural History, Fort Hays State University