DOI: 10.5061/dryad.bnzs7h4nk
title: How absolute biomass intake can alter nutrient profile interpretation in free-ranging species: The case of protein intake in brown bears

description: If an animal eats a large amount of a diet of a low content of a
 macronutrient, it can still ingest a considerable amount of that
 macronutrient. Various animals have been shown to balance nutrient content
 with intake in this way. We use the brown bear (Ursus arctos) as a model
 species, given their recent classification as ‘low protein omnivores’, to
 show how taking biomass intake into account can affect macronutrient
 intake interpretation. We 1) calculated absolute protein intake from
 published results of self-selection diet studies with bears in captivity
 and 2) modelled absolute protein intake of Swedish brown bears in autumn
 while binging on a berry diet of low protein concentrations. In feeding
 experiments in captivity, the self-selected macronutrient composition of
 brown bear diets are characterized by protein percentages (both on a dry
 matter and metabolizable energy basis) that appear low when compared to
 diets of carnivores. However, when taking into account absolute food
 intake and expressing this as daily protein intake per metabolic body mass
 (33-117 g/kg0.75/d), protein intake was considerably higher than
 established minimum requirements for domestic dogs and cats (2.6-3.8
 g/kg0.75/d) – carnivores one would not consider ‘low protein specialists’.
 Our hypothetical berry model yielded a protein intake of 3.2-9.7
 g/kg0.75/d, which is lower than the outcomes from the self-selection
 trials but still comparable to established requirements of domestic dogs
 and cats. Instead of perceiving bears as low-protein consumers, it might
 be more accurate to perceive them as temporary hyperphagia specialists for
 which low protein concentrations are necessary to avoid dramatically
 overshooting protein requirements. Including absolute food intake in diet
 determination offers important nuances in result interpretation. When
 coining labels to categorize animals, it may be advisable to not only
 consider nutrient concentrations but also absolute intake.
description: # How absolute biomass intake can alter nutrient profile interpretation in
 free-ranging species: The case of protein intake in brown bears Dataset
 DOI: [10.5061/dryad.bnzs7h4nk](10.5061/dryad.bnzs7h4nk) ## Description of
 the data and file structure The datafile represents the calculations
 explained in the manuscript. All the original data is either from the
 cited sources, or are assumed based on assumptions explained in the
 manuscript. ### Files and variables #### File:
 ADC\_DataCalculationsAll\_250324.xlsx **Description:** The datafile
 contains four spreadsheets that explain the calculations made for the
 manuscript. The first spreadsheet is for all calculations relating to
 brown bears, the second spreadsheet for calculations relating to sloth
 bears, the third spreadsheet for calculations related to Giant pandas, and
 the fourth spreadsheet for calculations related to the remaining
 carnivores of the manuscript, including domestic dogs, wolves, domestic
 cats and feral cats. The calculations always follow the same principle and
 only differ in the way that data extracted from the original sources had
 to be arranged and transformed to produce comparable results. #####
 Variables applying to all calculations * body weight (BW) (kg) * metabolic
 body weight (calculated as body weight to the power of 0.75) * intake
 (expressed in fresh or dry matter in kg, and as % of body mass * dry
 matter (DM, concentration in fresh matter) * crude protein (CP) in % dry
 matter or in kg, in % of metabolizable energy (ME), and in g per metabolic
 body weight * minimum and maximum (of ranges given in publications) *
 intake rate (g per minute) * foraging time (hours per day) * digestibility
 (the percentage of DM or CP ingested that is actually digested, i.e. not
 excreted via faeces) ## Code/software The calculations are made in EXCEL
 using simple mathematical equations. ## Access information Other publicly
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