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Pseudacris hypochondriaca   (Hallowell, 1854)

Common Name: Baja California Chorus Frog

Synonyms and Other Names: San Lucan chorus frog, Pseudacris regilla

Taxonomy: available through

Identification: Pseudacris hypochondriaca is a small hylid (treefrog) with a SVL (snout-vent length) of 19-50 mm (0.75-2 in) and small toe pads (disks) (Stebbins, 2003). The dorsal coloration of these color-changing, sometimes mottled, frogs also varies genetically:  green, reddish, tan, gray, brown, or black, but typically green or shades of brown (Stebbins, 1972, 2003; Lamar, 1997; Brennan and Holycross, 2006).  Unlike Pseudacris cadaverina, the California chorus frog, a black or dark brown eyestripe or mask is more often present, green is the more common dorsal color, and the toe pads are not as large and conspicuous (Stebbins, 2003).  Unlike Hyla wrightorum, the Arizona mountain treefrog, the eyestripe rarely extends beyond the shoulder (Powell et al., 1998; Grismer, 2002; Stebbins, 2003; Brennan and Holycross, 2006).  See the species account titled “Hyla wrightorum Taylor, 1938” on this website. Distinct morphological criteria for distinguishing P. hypochondriaca from its sister species the Pacific chorus frog, Pseudacris regilla, have not yet been established. See the species account titled “Pseudacris regilla (Baird and Girard, 1852)” on this website. The Baja California chorus frog’s call is the stereotypical, loud, two-part “kreck-ek” or “ribbit” most commonly used on Hollywood movie soundtracks regardless of the locality depicted in the movie (Davidson, 1995, 1996; Bogert, 1998; Stebbins, 2003; Beltz, 2005). Recordings of their calls are even used for plastic toy and novelty frogs. It is shorter, lower-pitched, and less musical than the call made by P. cadaverina (Stebbins, 2003). Recordings of the calls of P. hypochondriaca are widely available on CDs, but under the name P. regilla (Wilson, 1993; Elliott, 1994; Davidson, 1995, 1996; Bogert, 1998). The tadpoles of P. hypochondriaca are light greenish gray or olive brown, have high tail fins, and the internal viscera can be seen ventrally (Stebbins, 1972, 2003).

Baja California chorus frogs have been illustrated by a variety of authorities under the name Pacific chorus frog (Test, 1989; Wright and Wright, 1949; Stebbins, 1972, 1985, 2003; Smith, 1978; Behler and King, 1979; Kricher, 1993; Stebbins and Cohen, 1995; Lamar, 1997; Grismer, 2002; Beltz, 2005; Brennan and Holycross, 2006). Halliday (2002) illustrates skeletal deformities found in natural populations.

Size: SVL is 19-50 mm

Native Range: Pseudacris hypochondriaca is indigenous to Pacific and western regions of North America, from Nevada, most of southern California (except for some desert regions, but including some offshore islands), northwestern Arizona (Mohave County along the Colorado River), and Baja California, Mexico (Test, 1898; Stebbins, 1954, 1972, 2003; Jameson et al., 1966; Glaser, 1970; Smith and Smith, 1973, 1976, 1993; Flores-Villela, 1993; Lamar, 1997; Duellman and Sweet, 1999; Grismer, 2002; Brennan and Holycross, 2006; Recuero et al., 2006a; Luja et al., 2007).