Hamsters in the city: A study on the behaviour of a population of common hamsters (Cricetus cricetus) in urban environment

A validated LC-MS/MS method for simultaneous determination of key glucocorticoids in animal hair for applications in conservation biology

A new method for the determination of main glucocorticoids (cortisol, cortisone, and corticosterone) in hair by liquid chromatography-tandem mass spectrometry was developed. Glucocorticoids were extracted from hair shafts using methanol followed by solid-phase extraction. A validation test was performed using hair from three species of wild mammals with different body size (0.2-800 kg), lifestyle (terrestrial, burrowing and arboreal species), social organization (living in herds or solitary), and different predicted type of hair glucocorticoids: European bison (Bison bonasus), European hamster (Cricetus cricetus), and Eurasian red squirrel (Sciurus vulgaris). Regardless of the species evaluated, the method shows good linearity for all analytes accompanied by satisfactory accuracy (91-114%) and precision (RSD < 13%). Depending on the analyte and hair origin, the calculated limits of quantification were between 0.05 and 1.19 ng/mL, which corresponds to 1.28-31.51 pg/mg. Using cortisol and cortisone as examples, we have demonstrated that measuring multiple glucocorticoids simultaneously provides more comprehensive information than solely concentrating on one, thereby contributing to a more balanced and reliable interpretation of the acquired results. However, the utility of cortisol metabolites as markers of stress response in keratinized tissues should be substantiated by additional experimental studies on targeted animals. We posit that this paper could serve as a crucial catalyst to prompt such experiments.

When to Return to Normal? Temporal Dynamics of Vigilance in Four Situations

Vigilance is an important behaviour to monitor the environment from detecting predators to tracking conspecifics. However, little is known about how vigilance changes over time either without disturbance (vigilance decrement) or after a change occurred. The time course of vigilance can indicate how animals perceive a situation and the potential mechanism used to deal with it. I investigated the time course of vigilance in Gouldian Finches in four situations (familiar environment, two changed environments–novel object at a neutral location (exploration trial) or above the feeder (neophobia trial), novel environment). The frequency of head movements was assessed in four consecutive 15-min blocks in same sex pairs with a high frequency generally seen as indicative of high vigilance. Vigilance decreased over time in the familiar situation indicating vigilance decrement with a similar time course in the exploration trial. Vigilance was consistently high in the neophobia trial and only returned to normal in the last block. Finally, vigilance plummeted in the novel environment and did not return to normal within an hour. Results suggest that perceived threats affected vigilance and that information gathering reduced uncertainty allowing vigilance to return to normal levels but with different time courses depending on the situation.

Influence of landscape transformation and anxiety factor on the distribution of burrows of the Common hamster (Cricetus cricetus L., 1758) (Rodentia: Cricetidae) in the conditions of the park zone of the city of Simferopol

Based on our analysis of long-term (2015–2021) observations carried out at a registration spot in the park named after Yu. A. Gagarin (Simferopol, Crimea), patterns were revealed in the spatial distribution of burrows of the Common hamster (Cricetus cricetus L., 1758) depending on the state of the tree and shrub layer, as well as disturbance factors. It is shown that the leading factor influencing the spatial distribution of burrows is the location of trees, and the total number of burrows is mainly affected by the projective covering by shrubs; these factors were revealed as a result of cluster analysis for the spatial-geographical formulation of the problem and crosscorrelation analysis. It is assumed that the use of spatial modeling makes it possible to identify environmental factors, including plant communities, influencing the choice and exploitation of microhabitats by animals, as well as to find approaches to the analysis of the implementation of behavioral patterns during the development and exploitation of a habitat.

Curcumin-loaded nanocomplexes: Acute and chronic toxicity studies in mice and hamsters

We recently developed a modified solid dispersion of curcumin-loaded nanocomplexes (CNCs) in gums which promoted the prolonged and sustained release of curcumin. However, its safety assessment has not yet been investigated. Here, acute and chronic toxicities of CNCs were assayed using mice and hamsters. CNCs were orally administered to the animals. Doses of CNCs used for acute toxicity testing were 0.1, 1.1, 11.0 g/kg body weight for mice and 0.2, 2.1 and 21.4 g/kg body weight for hamsters. Doses of CNCs for chronic toxicity testing were 0.09, 0.27, 0.8 g/kg body weight/day for mice and 0.18, 0.54 and 1.61 g/kg body weight/day for hamsters. This regimen was followed daily for 6 months. Low and medium doses of CNCs did not induce any side effects in acute and chronic toxicity tests in either animal species. However, in acute toxicity testing, the organ-weight to body-weight ratio of spleen was significantly increased in mice treated with 11 g/kg body weight along with elevated levels of some biochemical parameters. There was a significant increase in organ-weight to body-weight ratios of stomach, liver and heart in hamsters treated with 21.4 g/kg body weight, but no elevated levels of biochemical parameters. Oral LD50 of CNCs in mice and hamsters were 8.9 and 16.8 g/kg body weight (equivalent to 2.5 and 4.7 g curcumin/kg body weight), respectively. Daily CNCs high-dose treatment for 6 months significantly increased organ-weight to body-weight ratios of stomach and intestine in mice and of lung and heart in hamsters. Elevated levels of glucose, total protein, ALT, AST and globulin in mice, and increased levels of AST, but decrease in cholesterol, in hamsters were concurrently observed with inflammation in liver and lung. These abnormalities were resolved within 28 days after cessation of treatment. The no-observed-adverse-effect level of CNCs was determined at 0.27 and 0.54 g/kg body weight/day in mice and hamsters. In conclusion, toxicity of high-dose CNCs treatment was graded as very low, possibly due to the components of the nanocomplex.