Two subspecies are recognized: Apalone mutica mutica (LeSueur, 1827) and Apalone mutica calvata (Webb, 1959). Apalone m. calvata has been listed as a separate species, A. calvata, in some field guides (Guyer et al. 2016, Powell et al. 2016). Further investigation into geographic distribution and genetic differences will be necessary in order to evaluate whether to elevate calvata to species level (Iverson et al. 2017).

Apalone mutica has a large geographic range with localized healthy populations and is assessed as Least Concern (LC). However, many states have listed it as a species of concern within their Wildlife Action Plans because of the lack of observations, decreased available habitat, road mortality, and/or nest predation. Population monitoring is seldom performed and regularly cited population estimates are possibly out of date. Because there is no continued monitoring across its range, we can only estimate whether A. mutica is experiencing population declines. The species is cryptic and difficult to monitor in its preferred habitat (turbid medium to large rivers, often with fast currents). Count surveys are difficult because of its elusive nature, hand capture via snorkelling is difficult because of turbid water conditions, and trapping has variable success. Continued degradation of waterways and adjacent terrestrial habitats will likely lead to further population declines. Flooding frequency changes due to climate change and dams can cause nest failure and the loss of sandbar nesting habitat which could lead to lower recruitment and an overall population decline. The species was previously assessed as Least Concern (LC) (van Dijk 2011), and both the species and the nominate subspecies A. m. mutica are reassessed at the same level at this time, although both are relatively Data Deficient (DD) and need improved monitoring. The subspecies A. m. calvata has a much smaller global distribution than A. m. mutica and remains understudied when compared to A. m. mutica and is assessed as Data Deficient (DD) or possibly Near Threatened (NT).

Apalone mutica occupies the greater Mississippi basin and Gulf of Mexico-associated tributaries from Western Florida to Central Texas, eastern New Mexico and eastern Colorado, and as far north as North Dakota and Minnesota and Wisconsin (TTWG 2021). Historically, A. mutica occupied western Pennsylvania but has been extirpated from that state (Hulse et al. 2001), as it also appears to have been from eastern Ohio (Krusling and Davis 2021). Apalone mutica mutica is distributed in the Mississippi basin west of the Appalachian Mountains, and western rivers to central Texas (see Figure S1 in the Supplementary Information). Apalone mutica calvata occurs in the Pearl, Alabama, and Escambia River systems of the southern Gulf plain (see Figure S1 in the Supplementary Information).

The estimated historical indigenous range (area of occupancy, AOO) of A. mutica was 632,580 sq. km, and the estimated historical indigenous extent of occurrence (EOO) was 2,875,453 sq. km (TTWG in press). For the subspecies A. m. mutica and A. m. calvata, the historical ranges (AOO) were 599,766 and 32,814 sq. km, respectively (TTWG in press). However, the current AOO for each subspecies is smaller, with portions of the range of A. m. mutica in eastern Ohio and western Pennsylvania extirpated, as well as a lack of records in the lower Alabama and Tombigbee rivers, suggesting that A. m. calvata could potentially have been extirpated from there, although it may simply reflect limited surveying. The current estimated AOO of A. m. calvata, based on all known locality records, appears to be significantly less than 10,000 sq. km, with a current EOO of less than 30,000 sq. km.

Population size, density, and abundance of Apalone mutica varies throughout much of its North American range. Plummer (1977b) estimated the A. mutica population of a 12 km section of the Kansas River to be 1,400 males and 550 females. Conversely, Bodie et al. (2000) captured only 57 A. mutica in a 295 km tract of the lower Missouri River between 1996 and 1998.

Plummer (1977b) counted 88 basking A. mutica on a 100-metre sandbar in the Kansas River and Trauth et al. (2004) estimated 1.2 A. mutica per linear river metre in Arkansas.

While not a population estimation per se, Doody (1995) and Godwin (2017) found identical numbers of both A. mutica and A. spinifera nests on the Comite River in southeastern Louisiana suggesting similar population sizes. Baited hoopnet traps on the Comite River overwhelmingly attracted A. spinifera and it is speculated baited hoopnets are not useful for A. mutica calvata (J.S. Doody pers. comm., May 2023).

While population estimates have suggested high densities, few modern monitoring attempts are underway and the often-cited population estimation studies are approaching 50 years old. Modern, range-wide surveys for A. mutica are critical in order to evaluate population stability.

Apalone mutica typically occupies large open bodies of water and in main or open channels within medium to large rivers typically with fast currents (Dickerson et al. 2009, Ernst and Lovich 2009). Occasionally, A. mutica will occupy water bodies adjacent to larger flowing water bodies or water bodies that become connected to larger flowing systems during the flood stage. Water bodies with soft sandy or silty bottoms are preferred as this species readily buries itself under substrate. Sand bars or mudbanks are preferred as they are used for basking and nesting (Williams and Christiansen 1981). Female A. mutica will often forage in deeper parts of the river than male A. mutica, which typically stay near the shore and occupy shallower waters (Plummer 1977a).

Apalone mutica eats a wide variety of aquatic invertebrate prey (Ernst and Lovich 2009, Cochran and Peterson 2011). While invertebrates are the primary food source, A. mutica will occasionally consume vegetation, fish, and fish carrion (Plummer and Farrar 1981). Like most omnivorous turtles, the species is opportunistic and will consume an array of prey items given the chance.

Breeding occurs from April through August, after emerging from hibernation (Plummer 1977b). Nesting season occurs from late May until August, especially in the south, but shorter in the north. Female A. mutica lay their eggs in sandbars and exposed ridges with little vegetation adjacent to the river between 4 and 90 m from the water on natural sandbars (Fitch and Plummer 1975, Ernst and Lovich 2009, Dixon 2009). However, on man-made sandbars, female Apalone spp. have been documented traveling up to 175 m from the water, likely due to man-made slopes having a lower slope (2.8°; Dixon 2009). Nests close to the water on steep banks and sandbars revealed that height is the variable chosen by females and that distance is simply a function of height above water (Doody 1995). Apalone spp. have a shorter incubation period than other turtle species, ranging from 48 to 82 days (Janzen 1993). Incubation is negatively related to temperature and hatching occurs from August through September (Janzen 1993). In South Dakota, there was an average of 14 eggs in a clutch with an average depth of the top egg being 9 cm (Dixon 2009). Communal overwintering of A. mutica and movements of >20 km within the river corridor have been documented in Minnesota (C.D. Hall pers. comm.).

Maximum size (straight-line carapace length, SCL) of A. m. mutica males is 26.6 cm and females 35.6 cm; for A. m. calvata the maximum SCL for males is 18.0 cm and for females 28.7 cm (Mount 1975, Barko and Briggler 2006, Moler 2006, Ernst and Lovich 2009, Krysko et al. 2019).

Hatchlings are between 30.0–36.7 mm (average 35 mm) SCL (Ernst and Lovich 2009).  Smooth softshell turtle clutch sizes can range from 1 to 33 eggs but average clutch sizes range from 6-8 eggs. (Fitch and Plummer 1975, Doody 1995, Moler 2006, Godwin 2017). Incubation time for smooth softshell turtle eggs is 44–82 days depending on the internal nest temperature (Janzen 1993, Plummer et al. 1994). Female A. mutica can lay two or three clutches per year (Lindeman 2001, Moler 2006). Generation time is not known, but is assumed to be ca 10–12 yrs, similar to the congener A. spinifera.

Male A. mutica reach maturity at 4 yrs and a plastron length of 8-8.5 cm and female A. mutica reach maturity at nine yrs with a plastron length of 14–15 cm (Plummer 1977c). While no current data exist on the longevity of smooth softshell turtles in the wild, it is suspected they can live 20 years or more (Ernst and Lovich 2009).

Habitat loss and degradation are likely the primary threats to Apalone mutica. Its reliance on rivers, and the microhabitats within those rivers, makes it especially susceptible to degradation and modification. Dewatering due to agriculture and drought is considered a major threat to fish and other aquatic fauna in western Great Plains rivers, one can assume this includes A. mutica as well (Haslouer et al. 2005). Channelizing of rivers in Iowa was implicated as the cause for softshell turtle population declines (Christiansen 1981). River channelizing creates homogenous environments and can reduce foraging and nesting sites. The species is likely impacted by pollution of waterways as it causes degradation of the aquatic habitat (Trauth et al. 2004). Flooding frequency changes due to climate change and dams can result in nest failure and the loss of sandbar nesting habitat leading to reduced recruitment (Plummer 1976, Doody 1995, Godwin 2017). 

Nest predation is a known threat that increases when nesting sites are closer to forest edges, which increases due to habitat fragmentation (Temple 1987, De Solla et al. 2003). In at least one river, all-terrain vehicle (ATV) recreation on A. mutica nesting beaches was responsible for a third of all nest mortality (Godwin et al. 2021). Turtle fraservirus 1 (TFV1) has not been detected or reported in A. mutica yet but has been implicated in Apalone ferox die-off events. Care in the transportation of turtles and monitoring for this pathogen should be a top priority. Human harvest, for both domestic and international markets, occurs in the species (Ceballos and Fitzgerald 2004) and needs continued monitoring. At individual and population levels, drowning in nets (bycatch), fishhook ingestion, boat strikes, and water diversion and infrastructure are a problem (Barko et al. 2004, Fratto et al. 2008, Bury 2011, Steen et al. 2014).

Adult Apalone mutica are likely exported as food to East Asia, and juveniles are sold for the pet trade. Apalone mutica is not nearly as common in the US pet or commercial trade as A. spinifera and A. ferox. Some states allow the harvest of A. mutica but records on harvest rates are scarce. Ceballos and Fitzgerald (2004) reported values of $3.00 to $10.89 USD per kg for turtle meat sold in Texas (turtle species unknown, but presumably Chelydra serpentina and/or Apalone spp.).

Declared exports of A. mutica are recorded in the USFWS Law Enforcement Management Information System (LEMIS) database, but available numbers do not reliably allow separating the data by area of origin or whether collected from the wild or produced in captive conditions. Numbers of live specimens identified as A. mutica exported from the USA were 10,000 or less annually during 1999–2009, but less than 5,000 annually in several of those years, and less than 1,000 in some years; no specimens have been recorded as being exported in any year from 2010 through 2019, but whether this reflects accurate species identification is questionable. In total, only about 36,500 live specimens were declared to have been exported during 2000–2019 (see Figure S2 in Supplementary Information for annual declared numbers of A. mutica, A. spinifera, and A. ferox).

Protection of lotic riverine systems, and a sizeable terrestrial buffer adjacent to the river, within the the range of Apalone mutica is vital for its survival. Channelizing and homogenizing rivers removes microhabitats necessary for foraging and nesting. Pollution of the waterways can directly and indirectly impact the survival of this species. Reducing the risk of nest predation (i.e., from feral swine, raccoons, and coyotes) may require predator exclusion cages or lethal control.

While most states within the range of A. mutica regulate the take and export of turtles, some states have little or no regulation regarding the specific take of A. mutica. Evaluation and modification of these state laws are necessary and recommended.

The species has a broad distribution but monitoring programmes have not been established in most states. Resources should be allocated to estimate and monitor A. mutica populations. According to NatureServe (2024), this is a Secure (G5) species in North America, but this was last reviewed in 1996 and needs to be updated. Natural Heritage Programs in South Dakota, Minnesota, Wisconsin, Missouri, New Mexico, Texas, Louisiana, and Indiana have it ranked as Vulnerable (S3),  Nebraska, Illinois, and Ohio Natural Heritage Programs consider it Imperiled (S2), whereas Colorado and Florida rank it as Critically Imperiled (S1). The species is apparently extirpated in Pennsylvania.

The species has been listed by CITES in Appendix II as Apalone spp. since 2023; previously it was listed in Appendix III (USA) since 2016.