Question

Whales and dolphins are hypothesized to have evolved along the northern shore of the Tethys Sea, prior to the Indian plate’s collision with the Eurasian plate. To which one of the following animals are these aquatic mammals most closely related?

• A. pigs
• B. elephants
• C. seals
• D. zebras

Hint:

If “hippos” isn’t an option, pick another \textbf{artiodactyl} (e.g., pigs, deer, camels) as the closest relative to whales/dolphins—never carnivores, perissodactyls, or afrotheres.

Answer 1

The Correct Option is A

Step 1: Recall the current phylogeny of Cetacea.
Molecular and fossil evidence places whales and dolphins (order \textit{Cetacea}) inside the even-toed ungulates (\textit{Artiodactyla}); together they form \textit{Cetartiodactyla}. Their closest living relatives are hippos.

Step 2: Map each option to major mammalian clades.

Pigs — artiodactyls (same larger clade as hippos and, by extension, cetaceans).
Elephants — Afrotheria (\textit{Proboscidea}); distant.
Seals — Carnivora (pinnipeds); distant.
Zebras — odd-toed ungulates (Perissodactyla); distant. The option closest to cetaceans among those listed is pigs (shared membership within Artiodactyla). Final Answer:
\[ \boxed{\text{(A) pigs}} \]