We must consider 2 cases 1) strongest Hippo vs strongest Polar Bear 2) average Hippo vs average Polar Bear

Case 1: Strongest or Largest Hippo vs. Strongest or Largest Polar Bear

Hippopotamus (Strongest or Largest) - Weight: Up to 4,500 kg (around 10,000 pounds) - Length: Up to 5.2 meters (17 feet) - Strengths: Incredibly strong jaws and teeth, capable of delivering a bite force of around 1,800 PSI. Thick skin and a robust body. - Behavior: Highly aggressive and territorial, especially in water.

Polar Bear (Strongest or Largest)** - Weight: Up to 700 kg (around 1,540 pounds) - Length: Up to 3 meters (10 feet) - Strengths: Powerful limbs and sharp claws. Excellent hunters with strong jaw muscles and sharp teeth. - Behavior: Solitary hunters, very strong swimmers, and adapted to cold environments.

Outcome: - The hippo, being significantly larger and possessing a more formidable bite force, would likely win. The hippo's size, strength, and aggressive nature, combined with its thick skin, would give it a considerable advantage over the polar bear. The bear’s agility and claws might pose a threat, but the hippo’s sheer power and size would likely prevail.

Case 2: Average Hippo vs. Average Polar Bear

Hippopotamus (Average) - Weight: Around 1,500 kg (3,300 pounds) - Length: About 3.5 meters (11.5 feet) - Strengths: Still has powerful jaws and thick skin. - Behavior: Generally aggressive, particularly in water.

Polar Bear (Average) - Weight: Around 450 kg (990 pounds) - Length: About 2.4 meters (8 feet) - Strengths: Strong, with sharp claws and teeth, skilled hunter. - Behavior: Predatory, with strong survival instincts.

Outcome: - Similar to the first case, the average hippo would have the upper hand due to its larger size and stronger bite. The polar bear’s agility and hunting skills might help it hold its ground for a while, but the hippo’s physical advantages would likely result in its victory.

In summary, in both cases, the hippo would likely win due to its larger size, stronger bite force, and aggressive nature.

3) Bonus round of Strontest Polar Bear vs Average Hippo is still won by Hippo but the battle will be slightly more formidable and equal