extra dependencies listed for urdf_tutorials?

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While listing out the dependencies of the package urdf_tutorials using sudo apt-cache depends ros-kinetic-urdf-tutorials, I am obtaining the list :

  Depends: ros-kinetic-joint-state-publisher
  Depends: ros-kinetic-pr2-description
  Depends: ros-kinetic-robot-state-publisher
  Depends: ros-kinetic-rviz
  Depends: ros-kinetic-urdf
  Depends: ros-kinetic-xacro

However, when I refer to the documentation ( http://wiki.ros.org/urdf_tutorial ), there are more dependencies listed. So, why aren't these extra ones displayed with sudo apt-cache depends. Also, cross checking with the package.xml file, I have noticed that this command is displaying only the runtime dependencies of a package. Is it the case?