You can't teach an old dog new tricks. Why not ? Is the dog too old to learn? Is the trainer not patient enough ? Are the old tricks still good enough? Is there need for new tricks? Is it just one dog or all the dogs? How big was the dog sample size before this hypothesis ?
I believe in causality, f*** around and find out. There's a swahili saying "ukiona vyaele jua vimeundwa." You may not notice the effort but just like the duck, beneath all the calm and effortless gliding we're busy paddling.
Tingiza mti or go plant one .
Happy mazingira day!