Complex sentence: They are more successful when hunting alone than when "teaching" juveniles, suggesting that a cost is incurred, and case studies suggest that juveniles taught the stranding technique by adults are able to master it more than a year earlier than their untaught peers.
Split into simpler sentences: They are more successful when hunting alone than when "teaching" juveniles, suggesting that a cost is incurred. And finally, case studies suggest that juveniles taught the stranding technique by adults are able to master it more than a year earlier than their untaught peers.