Pup ultrasonic isolation calls of six gerbil species and the relationship between acoustic traits and body size

Abstract

Among Gerbillinae rodents, ultrasonic calls of adults of small-sized species are typically higher frequency than those of adults of large-sized species. This study investigates whether a similar relationship can be found in pups of six gerbil species ( Dipodillus campestris , Gerbillus perpallidus , Meriones unguiculatus , Meriones vinogradovi , Sekeetamys calurus and Pachyuromys duprasi ). We compared the average values of acoustic variables (duration, fundamental and peak frequency) of ultrasonic calls (20 calls per pup, 1200 in total) recorded from 6- to 10-day-old pups (10 pups per species, 60 in total) isolated for 2 min at 22°C and then weighed and measured for body variables. The longest calls (56 ± 33 ms) were found in the largest species, and the highest frequency calls (74.8 ± 5.59 kHz) were found in the smallest species. However, across species, call duration (ranging from 56 to 159 ms among species) did not display a significant relationship with pup body size; and, among frequency variables, only the minimum fundamental frequency depended on pup body size. Discriminant analysis assigned 100% of calls to the correct species. The effect of species identity on the acoustics was stronger than the effect of body size. We discuss these results with the hypotheses of acoustic adaptation, social complexity, hearing ranges and phylogeny.

Discomfort-related changes of call rate and acoustic variables of ultrasonic vocalizations in adult yellow steppe lemmings Eolagurus luteus

“…This study investigated also the methodical point of the effects of presence/absence of frequency jumps on measurements of discomfort-related acoustic variables. This brief investigation is important for further research of USV variables in rodents, because frequency jumps are enormously widespread in pup and adult rodent USVs 6 , 9 , 14 , 30 – 32 . This most frequent nonlinear phenomenon affects very strongly the values of USV fundamental frequency.…”

“…Inspection of spectrograms and acoustic measurements have been conducted with Avisoft SASLab Pro software (Avisoft Bioacoustics, Berlin, Germany) and exported to Microsoft Excel (Microsoft Corp., Redmond, WA, USA). Following 14 , 32 , 39 , we defined the USV as frequency contour either continuous without breaks or with breaks shorter than 10 ms. If the separation break exceeded 10 ms, we considered that the contours belonged to two different calls.…”

Aerodynamics and motor control of ultrasonic vocalizations for social communication in mice and rats

“…The notion that wall impingement is incongruent with laryngeal anatomy [ 28 ] is thus incorrect. However, given the large diversity of laryngeal morphology and life history found in the 1500 species of rodents [ 49 ], our data does not exclude that multiple mechanisms contribute to USV production in other rodents species, such as singing [ 50 , 51 ] or grasshopper mice [ 52 ], gerbils [ 53 , 54 ], and lemmings [ 55 ]. Shallow cavity tones [ 36 ] provide an alternative mechanism to explain the loud and sometimes below 20 kHz frequency USVs of rodent species with more pronounced alar and pouch structures and may be a wide-spread mammalian sound production mechanism that requires further investigation.…”

“…Interestingly, a small fraction of USVs in muroid rodents, such as domestic mice [ 61 ], lemmings [ 55 ], and gerbils [ 54 ], can contain multiple frequency trajectories, which have been referred to as harmonic [ 61 ], or biphonic calls [ 53 – 55 ]. Because distinctly modulated frequency trajectories can be observed these do not represent a different mode of the same tone.…”

Ontogeny of audible squeaks in yellow steppe lemming Eolagurus luteus: trend towards shorter and low-frequency calls is reminiscent of those in ultrasonic vocalization

“…Following the methods [ 7 , 47 ], before parturition, females of the captive population were checked three times per week for the appearance of a litter, and birth dates as well as the number of pups were recorded. The day of birth was considered zero day of pup life.…”