Figure 1.
Relationships among Odontoceti and Mysticeti, between Neoceti and Archaeoceti, and higher level taxa of Whippomorpha (Cetacea + Hippopotamidae)
Note that within Cetacea, the only ghost lineage (any length of time missing fossils as inferred from the phylogeny) is a short gap at the origin of Odontoceti. There is a large ghost lineage between Hippopotamidae and the base of Cetacea. The temperature curve shows a smoothed record for the deep sea, in turn a proxy for global climate.
Figure 2.
Spindle Cells in the Humpback Whale Anterior Cingulate Cortex
A large number of spindle cells (arrowheads) are found in the anterior cingulate and insular and frontopolar cortices. They exhibit an elongate morphology with clearly visible apical and basal dendrites, and frequent grouping in clusters. Scale bar = 100 μm.
Figure A.
Spectrograms of each of nine model sounds and the resulting imitation. The arrow points to the beginning of the dolphin's imitation.
Figure B.
Dolphin imitates the behavior of a human by using its tail as an analogy for a leg.
Figure 3.
Dolphins That Passed the Mark Test, Thus Demonstrating Mirror Self-Recognition
(Photo credit: Diana Reiss, Wildlife Conservation Society)