Pradyumna: "Such rasas are of different varieties. In the revealed scriptures the following twelve varieties of rasas are enumerated: 1) raudra, anger; 2) adbhuta, wonder; 3) śṛṅgāra, conjugal love; 4) hāsya, comedy; 5) vīra, chivalry; 6) dayā, mercy; 7) dāsya, servitorship; 8) sakhya, fraternity; 9) bhayānaka, horror; 10) bībhatsa, shock; 11) śānta, neutrality; 12) vātsalya; parenthood. The sum total of all these rasas is called affection, or love. Primarily, such signs of love are manifested in adoration, service, friendship, paternal affection, and conjugal love. And when these five are absent, love is present indirectly in anger, wonder, comedy, chivalry, fear, shock and so on. For example, when a man is in love with a woman, the rasa is called conjugal love. But when such love affairs are disturbed, there may be wonder, anger, shock, or even horror. Sometimes love affairs between two persons culminate in ghastly murder scenes. Such rasas are displayed between man and man and between animal and animal. There is no possibility of an exchange or rasa between a man and an animal or between a man and any other species of living beings within the material world. The rasas are exchanged between members of the same species. But as far as the spirit souls are concerned,..."
Prabhupāda: You have seen sometimes the pigeons fighting. But a pigeon and crow does not fight. A pigeon and pigeon fights. So this is also another indirect way of love. You'll see the pigeons, they will fight and again sit down in the assembly of the pigeons, not that the pigeon is going to the assembly of crows.