docs: def dens2lip(dens_gcm3, dens_lipid=0.9007, dens_prot=1.34, dens_water=0.994,
          dens_ash=2.3):
      '''Get percent composition of animal from body density
  
      The equation calculating animal density is from Biuw et al. (2003), and
      default values for component densities are from human studies collected in
      the book by Moore et al. (1963).
  
      Args
      ----
      dens_gcm3: float or ndarray
          An array of seal densities (g/cm^3). The calculations only yield valid
          percents with densities between 0.888-1.123 with other parameters left
          as defaults.
      dens_lipid: float
          Density of lipid content in the animal (g/cm^3)
      dens_prot: float
          Density of protein content in the animal (g/cm^3)
      dens_water: float
          Density of water content in the animal (g/cm^3)
      dens_ash: float
          Density of ash content in the animal (g/cm^3)
  
      Returns
      -------
      perc_all: pandas.DataFrame
          Dataframe of components of body composition
  
      References
      ----------
      Biuw, M., 2003. Blubber and buoyancy: monitoring the body condition of
      free-ranging seals using simple dive characteristics. Journal of
      Experimental Biology 206, 3405–3423. doi:10.1242/jeb.00583
  
      Moore FD, Oleson KH, McMurrery JD, Parker HV, Ball MR, Boyden CM. The Body
      Cell Mass and Its Supporting Environment - The Composition in Health and
      Disease. Philadelphia: W.B. Saunders Company; 1963. 535 p.
      ISBN:0-7216-6480-6
      '''
      import numpy
  
      # Cast iterables to numpy array
      if numpy.iterable(dens_gcm3):
          dens_gcm3 = numpy.asarray(dens_gcm3)
  
      # Numerators
      ad_num =  -3.2248 * dens_ash
      pd_num = -25.2786 * dens_prot
      wd_num = -71.4966 * dens_water
  
      # Denominators
      ad_den = -0.034  * dens_ash
      pd_den = -0.2857 * dens_prot
      wd_den = -0.6803 * dens_water
  
      perc_lipid = ((100 * dens_gcm3) + ad_num + pd_num + wd_num) / \
                          (dens_lipid + ad_den + pd_den + wd_den)
  
      return perc_lipid