Mammals body mass and basal Metabolic Rate Vs. Birds


Basal metabolic rate is the total amount of energy measured in calories required by an individual to maintain body functions such as breathing or circulation of blood when the body is at rest. (Briga and Verhulst 3280). This paper aims to determine whether a relationship exists between the body mass and the basal metabolic rate (BMR). Mammals and birds were the two classifications of animals chosen to investigate this relationship.

Materials and Methods

The material used for this paper were graphed from the data of the mammals and birds generated from Quaadvark. A sample of 302 species of mammals and 68 species of birds was used. The sample had different species with varying masses to obtain a conclusive result of the relationship between the two variables. The references used were book sources that discuss both basal metabolic rates and body weight and their relationship in both mammals and birds.

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Results: Two figures with legends and one paragraph stating results.

Figure1. Relationship between mammalian Basal Metabolic Rate (W) and body mass (g) from a sample of 302 Mammals

Figure2. Average Basal Metabolic Rate (W) against body mass (g) of 68 species of birds.

In both mammals and birds, the body mass was proportional to its BMR. A high body mass means a large number of cells which need more energy at rest, therefore, increasing the amount of energy required.


The results obtained and presented in the graphs above for both mammals and birds showed that a relationship does exist between the animal’s body mass and its Basal Metabolic Rate. Mammals with a higher body weight had higher levels of BMR and the same applied to mammals. The slight variations in birds may have been as a result of different variations in their environment such as temperature which could have influenced the BMR of those birds.


Works Cited

Briga, Michael, and Simon Verhulst. “Individual variation in metabolic reaction norms over ambient temperature causes low correlation between basal and standard metabolic rate.” Journal of Experimental Biology 220.18 (2017): 3280-3289.

Hudson, Lawrence N., Nick JB Isaac, and Daniel C. Reuman. “The relationship between body mass and basal metabolic rate among individual birds and mammals.” Journal of Animal Ecology 82.5 (2013): 1009-1020.

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