Hey there,
It’s intended that there’s no caravan version of a Greater Rhino. Caravan Rhinos have extra slot spaces (there’s been a slight confusion about this, our apologies), while Greater Rhinos have beefed up stats. Choosing between the Greater or Caravan version is a trade-off. Having both would be an advantage gameplay-wise, which would be against our aim with our DLC.
This can be confusing and lead to a loss of important pets as reported in this thread, so we’ll make sure to send note to our team and see if they could implement a way to warn players beforehand.