\name{Mammals}
\alias{Mammals}
\docType{data}
\title{Garland(1983) Data on Running Speed of Mammals}
\description{
Observations on the maximal running speed of mammal species
and their body mass.
}
\usage{data(Mammals)}
\format{
  A data frame with 107 observations on the following 4 variables.
  \describe{
    \item{weight}{Body mass in Kg for "typical adult sizes"}
    \item{speed}{Maximal running speed (fastest sprint velocity on record)}
    \item{hoppers}{logical variable indicating animals that ambulate
	by hopping, e.g. kangaroos}
    \item{specials}{logical variable indicating special animals with
	"lifestyles in which speed does not figure as an important
	factor":  Hippopotamus, raccoon (Procyon), badger (Meles),
	coati (Nasua), skunk (Mephitis), man (Homo), porcupine
	(Erithizon), oppossum (didelphis), and sloth (Bradypus)
	}
  }
}
\examples{
data(Mammals)
attach(Mammals)
x <- log(weight)
y <- log(speed)
plot(x,y, xlab="Weight in log(Kg)", ylab="Speed in log(Km/hour)",type="n")
points(x[hoppers],y[hoppers],pch = "h", col="red")
points(x[specials],y[specials],pch = "s", col="blue")
others <- (!hoppers & !specials)
points(x[others],y[others], col="black",cex = .75)
fit <- rqss(y ~ qss(x, lambda = 1),tau = .9)
plot(fit)
}

\details{
Used by Chappell (1989) and Koenker, Ng and Portnoy (1994) to
illustrate the fitting of piecewise linear curves.
}
\source{
Garland, T. (1983) The relation between maximal running speed and body 
mass in terrestrial mammals, \emph{J. Zoology}, 199, 1557-1570.
}
\references{
Koenker, R., P. Ng and S. Portnoy, (1994)  Quantile Smoothing Splines'' 
\emph{Biometrika}, 81, 673-680.

Chappell, R. (1989) Fitting Bent Lines to Data, with Applications ot
Allometry,  \emph{J. Theo. Biology}, 138, 235-256.

}
\seealso{\code{\link{rqss}}}
\keyword{datasets}