The total number of white blood cells (WBCs) is related the immune system. In mammals, it is affected by the body mass, but it is unclear how the numbers of different WBC types correlate with this parameter. We analyzed the effect of body mass on WBC number and ratio in felids, where species are similar in diet (warm-blood vertebrates) and reproductive strategy (promiscuity). Based on zoo veterinary data (ZIMS database) we analyzed the effect of body mass on WBC number and neutrophils/lymphocytes ratio in 26 species of felids. The number of WBCs correlated with the body masses of animals: large cats had more WBC, which may be due to greater risks of infection associated with larger body surface, lifespan and home range size. For the first time we found obvious differences in the number of WBC types. Large cats also had more neutrophils and monocytes but fewer lymphocytes than smaller cats. The ratio of neutrophils to lymphocytes is greater in large felids. This phenomenon may be related to diet (relative prey size and kill utilization time), which suggests regular contact of large cats with bacterial and protozoal pathogens in contrast to the small cats.

中文翻译：

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大小很重要：Zoo数据分析显示，大毛绒和小毛绒的白细胞比率不同。

白细胞（WBC）的总数与免疫系统有关。在哺乳动物中，它受体重影响，但尚不清楚不同WBC类型的数量如何与此参数相关。我们分析了体重对猫科动物白血球数量和比例的影响，这些猫科动物的饮食（温血脊椎动物）和生殖策略（滥交）相似。根据动物园的兽医数据（ZIMS数据库），我们分析了体重对26种猫科动物WBC数量和中性白细胞/淋巴细胞比率的影响。白细胞的数量与动物的体重有关：大猫的白细胞更多，这可能是由于更大的体表，寿命和家庭规模引起的感染风险增加。我们第一次发现WBC类型数量明显不同。大型猫也比小型猫具有更多的中性粒细胞和单核细胞，但淋巴细胞较少。大猫科动物中性粒细胞与淋巴细胞的比例更大。这种现象可能与饮食有关（相对的猎物大小和杀死利用时间），这表明与小型猫相比，大型猫经常与细菌和原生动物病原体接触。