Comparison of ultrasonic isolation calls of pure-breeding and interspecies hybrid Phodopus dwarf hamster pups.

In mammalian cross-species hybrids, parameters of voice calls, produced by vocal fold vibrations, are intermediate between parental species. Inheritance of ultrasonic calls, produced by whistle mechanism, is unstudied for hybrids. We examined 4000 pup ultrasonic isolation-induced calls for peak power of call fundamental frequency and for call duration in 4-8-day-old captive hamsters of four Study Groups: pure Phodopus sungorus; pure P.

On the winter enhancement of adaptive humoral immunity: hypothesis testing in desert hamsters (Phodopus roborovskii: Cricetidae, Rodentia) kept under long-day and short-day photoperiod.

We tested the winter immunity enhancement hypothesis (WIEH) on male desert hamsters (Phodopus roborovskii) kept under long-day (LD) and short-day (SD) photoperiods. We assumed that under SD in a laboratory, the adaptive humoral immune responsiveness to the antigenic challenge would be enhanced due to the lack of winter physical stressors and food shortages and/or because of the action of an endogenous winter bolstering mechanism, while under LD the immune responsiveness would be suppressed by the activity of the reproductive system. The results support the WIEH in part.

Females choose gentle, but not healthy or macho males in Campbell dwarf hamsters ( Thomas 1905).

Androgen-dependent male sexual traits (STs) as well as immunocompetence are theoretically assumed to be key indicators of a male's quality for the mate-choosing female. We studied mate choice by sexually motivated (SM) females of Campbell's dwarf hamsters. Females chose between 2 tethered male siblings that differed in expression of STs.

Effects of the mitochondria-targeted antioxidant SkQ1 on lifespan of rodents.

The effect of the mitochondria-targeted, plastoquinone-containing antioxidant SkQ1 on the lifespan of outbred mice and of three strains of inbred mice was studied. To this end, low pathogen (LP) or specific pathogen free (SPF) vivaria in St. Petersburg, Moscow, and Stockholm were used.