Pseudocerastes urarachnoides is a fascinating viper and as yet has been reported only in western Iran. An elaborated arachnid-like caudal structure is a unique feature of this viper, hence gives it the common name “Iranian spider-tailed viper”. During tail wagging, the structure is reminiscent of a moving spider. Tail movements are used for two different purposes in snakes: defense via tail vibration and hunting via both caudal luring and caudal distraction. Caudal luring in snakes is the wriggling or wagging of the posterior part of tail, in the presence of a potential prey, with conspicuous color pattern while the rest of body is cryptically colored. Previous studies have speculated on the role of caudal structure of P. urarachnoides in hunting. Our 2.5-year study has revealed that development of the structure of the caudal lure is commenced after birth and is linearly correlated to snout-vent length. The caudal lure attracts some species of birds. Caudal luring behavior is carried out both in the presence and absence of birds. The findings are reported for the first time and confirmed by direct observation of undisturbed individuals in the field.

The Vipera albicornuta is an economically important snake of Iran, its venom is used for antivenin production, and we need to breed the snake in the captivity. In order to know about the viper's reproductive biology, seasonal alterations in ovarian weight, morphology, and the follicles developmental stages in Vipera albicornuta were studied using macroscopic parameters and histological examination of reproductive tissues during a year. Twenty-four female vipers were collected from mountainous zone of Bostanabad, East Azerbaijan, and Tarom in Zanjan through years 2011-2012. Evaluation of the reproductive parameters of this viper is performed for the first time in Iran. Our observation revealed that vitellogenesis cycle begins in autumn and continues till early summer; ovaries and follicles are in previtellogenesis stage in autumn and vitellogenesis in winter and during spring. Weight of ovary is heaviest in spring, ovulation occurs in late spring till early summer, and copulation is prior to ovulation.

In this research, concentration of thyroid-stimulating hormone (TSH), triiodothyronine (T3), thyroxin (T4) and their relationship with body weight in Caucasian viper have been studied. The female Caucasian pitviper (n=26) were collected from Lar in Tehran province, the animal's body weight and length, and serum TSH, T3 and T4 levels were measured by electrochemiluminescence method during autumn, winter and summer in year 2014. The results showed T3 hormone concentration in autumn was 0.74± 0.06 nmol/Lt that was higher than its level in winter, 0.46± 0.8 Fani et al.; ARRB, 14(1): 1-9, 2017; Article no.ARRB.33828 2 nmol/Lt (P≤0.05) and no significant different with its concentration in summer 0.76 ± 0.05 nmol/Lt. The concentration of T4 hormone in autumn, 0.84±0.28 nmol/Lt was higher than winter 0.76±0.033 nmol/Lt (P≤0.19) and also summer 0.64 ±0.018 nmol/Lt (P≤0.001). TSH concentration was 0.005 nmol/Lt in autumn; reach to 0.013±0.008 nmol/Lt in winter and again 0.005 nmol/Lt in summer that shows relative increase in winter (P≤0.05). Mean body length and weight of female Caucasian vipers were 47.50±0.69 cm and 50.80±2.53 gram in autumn and 34.33±2.33 cm, 43.33±2.40 gram in winter and 51.64±1.26 cm and 64.78±3.47 gram in summer, respectively. This is indicated that Caucasian vipers' body weight is decreased in winter could be because of body fat consumption, inaccessibility to food and beginning of reduction of nutritional activity at the end of autumn compare to summer that may result to lower body weight in winter. Concentration of T3 and TSH hormone is decreased in summer and increased in winter. It seems by decreasing temperature in winter serum concentration of TSH is increased and viper`s body weight reduced (Fat consumption) to provide required energy and heat for Iranian Caucasian viper survival. So, seasonal and temperature variation has significant effect on Iran Caucasian viper`s thyroid hormones that is important for animal maintenance. Although further study is needed. Original Research Article

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